United States v. Wooldridge , 851 F.3d 91 ( 2017 )


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  •           United States Court of Appeals
    For the First Circuit
    No. 15-1812
    UNITED STATES OF AMERICA,
    Appellee,
    v.
    JAMES DUNSTON,
    Defendant, Appellant.
    No. 15-1999
    UNITED STATES OF AMERICA,
    Appellee,
    v.
    SERGIO HERNANDEZ,
    Defendant, Appellant.
    ____________________
    No. 15-2000
    UNITED STATES OF AMERICA,
    Appellee,
    v.
    ANTHONY WOOLDRIDGE,
    Defendant, Appellant.
    _____________________
    APPEALS FROM THE UNITED STATES DISTRICT COURT
    FOR THE DISTRICT OF MASSACHUSETTS
    [Hon. Timothy S. Hillman, U.S. District Judge]
    Before
    Barron, Circuit Judge,
    Souter, Associate Justice,
    and Selya, Circuit Judge.
    Peter J. Cyr, with whom Law Offices of Peter J. Cyr were on
    brief, for appellant Wooldridge.
    Michael D. Day, with whom The Day Law Firm, LLC was on brief,
    for appellant Hernandez.
    Xiomara M. Hernández on brief for appellant Dunston.
    Mark T. Quinlivan, Assistant United States Attorney, with
    whom Carmen M. Ortiz, United States Attorney, was on brief, for
    appellee.
    March 15, 2017
    
    Hon. David H. Souter, Associate Justice (Ret.) of the Supreme
    Court of the United States, sitting by designation.
    SELYA, Circuit Judge.    In cases in which defendants are
    accused of trafficking in narcotics, drug quantity is often both
    an element of the offense and a critical integer in the sentencing
    calculus.    These appeals illustrate that duality and, at the same
    time, serve to explicate the shifting standards of proof that
    pertain.      Because   the   court   below   applied   these   standards
    appropriately, we affirm both of the challenged convictions and
    two of the three challenged sentences.        With respect to the third
    sentence, though, the government concedes that the district court
    relied on too weak a foundation in classifying the defendant as a
    career offender and we are not persuaded by the government's
    attempt to brand the error harmless.          We therefore remand that
    sentence for further proceedings consistent with this opinion.
    I.   BACKGROUND
    We start with an overview of the case, drawing relevant
    facts from the trial transcripts, line sheets of recorded telephone
    calls introduced into evidence, and (where appropriate) undisputed
    portions of the defendants' presentence investigation reports.
    This case has its roots in an investigation into drug
    dealing in and around Worcester, Massachusetts, commenced by the
    Drug Enforcement Administration (DEA) and local police officers.
    The probe initially focused on defendants James Dunston and Sergio
    Hernandez.    Its scope later expanded to include defendant Anthony
    Wooldridge.
    - 3 -
    The   investigation     was     launched    with      a    number     of
    controlled buys: between January and June — all dates are in 2012
    unless otherwise indicated — an undercover DEA agent bought nearly
    forty-four grams of crack cocaine from Dunston and Hernandez in
    sixteen separate transactions.           Intelligence gained during these
    sorties furnished the basis for properly authorized wiretaps on
    both   Hernandez's    telephone    and     the    telephone   of       yet    another
    coconspirator (Richard Cruz).            Between June and September, the
    agents intercepted close to 30,000 calls and text messages.                       The
    wiretapped    intercepts   indicated       that    Dunston,     Hernandez,        and
    Wooldridge were regularly dealing crack cocaine in Worcester and
    its environs.
    The wiretaps revealed, inter alia, that the defendants
    acquired powder cocaine on no fewer than seven occasions in the
    summer months and attempted at least one further acquisition.
    Shortly   after    receiving   the    powder,      the   defendants          promptly
    converted it to crack.     They frequently discussed crack conversion
    techniques, described the results of particular conversions, and
    boasted about their ability to convert powder to crack without
    losing any appreciable drug weight.
    It is said that all good things come to an end and, in
    July, Wooldridge was arrested during a traffic stop after police
    officers conducted a pat-frisk and found ninety-three grams of
    crack cocaine on his person.         Dunston and Hernandez were arrested
    - 4 -
    in September.     All three were charged with conspiring to possess
    with intent to distribute both crack cocaine and powder cocaine.
    See 
    21 U.S.C. §§ 841
    (a)(1), 846.              Additionally, Wooldridge was
    charged with possession of crack cocaine with intent to distribute,
    see 
    id.
     § 841(a)(1), and Hernandez was charged with being a felon
    in   possession   of    a   firearm    and     ammunition,      see   
    18 U.S.C. § 922
    (g)(1).
    After some preliminary skirmishing, all three defendants
    waived indictment and pleaded guilty to superseding informations
    charging them with, as relevant here, conspiring to possess with
    intent to distribute crack cocaine.                The informations specified
    that the charged conspiracy "involved 280 grams or more of a
    mixture and substance containing a detectable amount of cocaine
    base" — a quantity sufficient to trigger a ten-year mandatory
    minimum sentence.      See 
    21 U.S.C. § 841
    (b)(1)(A)(iii).
    Each    defendant      pleaded      guilty      to   the   underlying
    conspiracy offense, reserving, however, the right to contest at a
    bench   trial   whether     the   amount      of   crack   cocaine    reasonably
    foreseeable or attributable to him was 280 grams or more (thus
    exposing him to the mandatory minimum sentence).                  The district
    court thereafter held an eight-day bench trial, at which it heard,
    inter alia, recordings of intercepted calls as well as testimony
    from a DEA agent (Timothy Boyle), who interpreted the slang and
    jargon that permeated in the recordings.             At the conclusion of all
    - 5 -
    the evidence, the court found "beyond a reasonable doubt that over
    280   grams    of   cocaine    base   [wa]s   attributable   and   reasonably
    foreseeable to all defendants."
    The district court ordered the probation department to
    prepare individual presentence investigation reports.                 At the
    disposition hearings, the court adopted the reports without change
    and classified all three defendants as career offenders under the
    sentencing guidelines.          It found Wooldridge responsible for at
    least 840 grams of crack cocaine and sentenced him to a 132-month
    term of immurement.          With respect to Dunston and Hernandez, the
    court found each of them responsible for at least 2.8 kilograms
    (2,800 grams) of crack cocaine; sentenced Dunston to 144 months'
    imprisonment; and sentenced Hernandez to 162 months' imprisonment.
    These timely appeals followed.
    II.   ANALYSIS
    The defendants' appeals have been consolidated, and we
    turn first to the claims of error that implicate their convictions.
    From that point, we proceed to their claims of sentencing error.
    A.    Lay Opinion Testimony.
    Dunston contends that the district court should not have
    allowed Agent Boyle to testify about the meaning of slang terms
    and jargon used in the course of the wiretapped conversations.            He
    submits that although Boyle may have been qualified to give some
    lay opinion testimony, the government failed to erect an adequate
    - 6 -
    foundation for his interpretations of particular slang terms.          To
    illustrate his point, Dunston notes that Boyle was allowed to
    testify that the word "tweezy" referred to crack cocaine and that
    the phrase "step up a yard" referred to turning powder into crack.
    In   Dunston's   view,   Boyle's   familiarity   with    the   defendants'
    conversations did not qualify him to give an informed opinion about
    the meaning of these and other specific phrases used within those
    conversations.    We do not agree.
    All three defendants raised this issue below, but only
    Dunston pursues it on appeal.         Objections to the admission of
    evidence are reviewed for abuse of discretion.          See United States
    v. Valdivia, 
    680 F.3d 33
    , 50 (1st Cir. 2012).           The parties agree
    that Agent Boyle's testimony should be considered lay opinion
    testimony.    Hence, Federal Rule of Evidence 701 controls.        See 
    id.
    Rule 701 permits the admission of lay opinion testimony "rationally
    based on the witness's perception" that would help the factfinder
    "determin[e] a fact in issue."
    Application of Rule 701 in the drug-trafficking context
    is not novel: "we have long held that government witnesses with
    experience in drug investigations may explain the drug trade and
    translate coded language" for factfinders through lay opinion
    testimony.     United States v. Rosado-Pérez, 
    605 F.3d 48
    , 56 (1st
    Cir. 2010); accord United States v. Hoffman, 
    832 F.2d 1299
    , 1310
    (1st Cir. 1987) (holding that "interpretation of codes and jargon
    - 7 -
    used in the drug trade can be supplied through one experienced in
    the field").   Such testimony is especially useful where, as here,
    it can afford the factfinder the benefit of specialized knowledge.
    See United States v. Albertelli, 
    687 F.3d 439
    , 446 (1st Cir. 2012).
    Of course, such interpretive testimony must be anchored
    in the witness's personal experience in the field, see Hoffman,
    
    832 F.2d at 1310
    , and his experience-based understanding of the
    meaning of the terms used, United States v. Prange, 
    771 F.3d 17
    ,
    28 & n.3 (1st Cir. 2014).     Put another way, "an interpretation of
    a phrase or reference ought to be explicable" — a standard that
    typically requires the witness to point to similar statements
    surrounding similar events.     Albertelli, 687 F.3d at 450.
    In the case at hand, the government erected a sturdy
    foundation for Boyle's testimony.      The record reflects that Boyle
    had a twenty-four-year career in law enforcement, with significant
    experience in undercover drug investigations.             He had received
    specialized training in narcotics enforcement, had participated in
    over fifteen wiretap investigations, and had supervised more than
    twenty other such investigations.         As part of his duties, he had
    reviewed    audio   and   videotape   from   undercover    crack   cocaine
    purchases "hundreds" of times and had taken part at least once in
    an undercover operation in which he observed powder being converted
    to crack.
    - 8 -
    In this particular probe, Boyle reviewed nearly all of
    the 30,000 calls and texts collected during the wiretaps.               He not
    only drew on his extensive experience to inform his understanding
    of specific slang terms but also took into account the context in
    which those terms were used.             Boyle explained that he often
    listened to "several calls leading up to" the use of a given bit
    of slang as well as "conversations that would take place after
    that" to ensure his understanding.
    Confronted with objections, the district court prudently
    allowed defense counsel to conduct a voir dire and question Boyle
    about his credentials, his experience, and his knowledge.                 This
    additional safeguard, coupled with Boyle's cross-examination by
    all three defense attorneys, mitigated any risk of unfair prejudice
    from his testimony.       See United States v. Henry, ___ F.3d ___, ___
    (1st Cir. 2017) [No. 15-2487, slip op. at 21]; Albertelli, 687
    F.3d at 447.
    Where malefactors try to mask their criminal activities
    by using codes, a law enforcement officer who is equipped by
    knowledge, experience, and training to break those codes can help
    to inform the factfinder's understanding.               So it is here: the
    government     provided   the   district    court   with     ample   reason   to
    conclude that Boyle was knowledgeable about the idiom of the drug
    trade   and,    in   particular,   the     vernacular   of    this   group    of
    miscreants.     On this record, we hold, without serious question,
    - 9 -
    that the admission of Boyle's lay opinion testimony was comfortably
    within the ambit of the district court's discretion.
    B.   Sufficiency of the Evidence.
    The next leg of our journey takes us to Dunston's and
    Wooldridge's claims that the district court lacked sufficient
    evidence to find them guilty of the charged offense.    These claims
    share a common focus: they are aimed at the district court's
    finding, at trial, that at least 280 grams of crack cocaine was
    "attributable and reasonably foreseeable" by the defendant making
    the claim.    Such a defendant-specific finding is an element of the
    offense of conviction: it means that a defendant cannot, simply by
    reason of his membership in a conspiracy that traffics in large
    amounts of drugs, automatically be "saddled with the full weight
    of the conspiracy's wrongdoing."      United States v. Sepulveda, 
    15 F.3d 1161
    , 1197 (1st Cir. 1993).     He can only be held responsible
    for drugs that he "personally handled or anticipated handling," as
    well as "drugs involved in additional acts that were reasonably
    foreseeable by him and were committed in furtherance of the
    conspiracy."     
    Id.
    Here, the district court held a bench trial on the drug-
    weight issue — a trial that was necessary because any fact that
    increases the mandatory minimum sentence for an offense must,
    absent a plea or a stipulation, be submitted to a factfinder to be
    determined beyond a reasonable doubt.        See Alleyne v. United
    - 10 -
    States, 
    133 S. Ct. 2151
    , 2155 (2013) (citing Apprendi v. New
    Jersey, 
    530 U.S. 466
    , 483 n.10, 490 (2000)); United States v.
    Pizarro, 
    772 F.3d 284
    , 292-93 (1st Cir. 2014).      At the end of the
    trial, the court found that each of the defendants was responsible
    for at least 280 grams of crack cocaine.
    Hernandez   does     not      appeal   the    drug-quantity
    determination as it relates to him.       Dunston and Wooldridge do
    appeal and, as to each of them, we must "examin[e] the facts and
    inferences in the light most favorable to the verdict."        United
    States v. O'Donnell, 
    840 F.3d 15
    , 18 (1st Cir. 2016) (citation
    omitted); cf. United States v. Colon-Solis, 
    354 F.3d 101
    , 103 (1st
    Cir. 2004) (requiring "defendant-specific determination of drug
    quantity" for this purpose).    The ultimate question is whether,
    after viewing the evidence in the light most hospitable to the
    government, a rational trier of fact could have found the drug-
    weight elements beyond a reasonable doubt.       See United States v.
    Grace, 
    367 F.3d 29
    , 34 (1st Cir. 2004).          We must answer this
    question separately as to each of the two appealing defendants,
    see Colon-Solis, 
    354 F.3d at 103
    , exercising de novo review.      See
    O'Donnell, 840 F.3d at 18.
    With this preface, we turn to the substance of the
    sufficiency claims.    We begin with Dunston and then move to
    Wooldridge.
    - 11 -
    1.   Dunston.   Dunston contends that the court's finding
    that he was responsible for at least 280 grams of crack cocaine
    was plucked out of thin air.        Pointing out that the authorities
    never seized any of the drugs to which he alluded in the wiretapped
    conversations, he insists that it remains unclear how much powder
    was converted to crack.
    Dunston is whistling past the graveyard.       The government
    presented evidence linking Dunston to at least eight separate
    transactions.    We need examine only two of these occurrences to
    defuse Dunston's attack.
    On June 26, the government intercepted a telephone call
    in which Dunston and Hernandez discussed their plans to cook 200
    grams of powder cocaine recently purchased from Wooldridge.          The
    two men split the contraband, and Dunston told Hernandez that he
    was going to "step up a yard right now and see what it is."         This
    meant, Agent Boyle testified, that Dunston intended to convert 100
    grams of powder into crack.    Later that day, Dunston and Hernandez
    spoke again.     When Hernandez asked, "how did that come out,"
    Dunston replied that the result was "[a]ll yellow" and that he
    "[g]ot back, like, 2 extra grams.      It was, like, 102 when it dried
    all the way out, bone dry."    Boyle testified that the yellow tinge
    of Dunston's product was emblematic of crack cocaine and that,
    since   converting   powder   to    crack   requires   water,   Dunston's
    - 12 -
    reference to drying the product was also consistent with making
    crack.
    When judges sit as factfinders, they are not obliged to
    put their common sense into cold storage.        Given the wiretaps and
    Boyle's testimony, the district court surely had a rational basis
    for   finding,   beyond   any    reasonable   doubt,   that   Dunston   was
    responsible for at least 200 grams of crack stemming from the June
    26 events.    For one thing, the court supportably could have found
    Dunston responsible for the 100 grams that he himself cooked.           For
    another thing, the court supportably could have found that the
    remaining 100 grams, retained by Hernandez, was to be converted
    from powder to crack as part of the conspiracy and that the
    conversion was reasonably foreseeable to Dunston.1
    Dunston protests.     He says that there is no evidence
    that this latter 100 grams of powder was actually converted to
    crack and that this part of the district court's drug-quantity
    calculation was faulty because it implicitly assumed that 100 grams
    of powder cocaine, when converted, would yield 100 grams of crack
    1For example, the court heard evidence that once Dunston told
    Hernandez that he "got back 2 . . . extra grams" after cooking the
    powder, Hernandez responded, "You should have done mine." Dunston
    replied, "You're the only one that didn't want me to do yours!"
    and indicated that Hernandez had mentioned planning to cook his
    powder in a particular type of pot. Several hours later, Hernandez
    called a third party and asked to use his kitchen.
    - 13 -
    cocaine.       He insists that, even in optimal conditions, 100 grams
    of powder cannot be converted into more than 89.2 grams of crack.
    This attack misfires.     The court had before it evidence
    that, on both June 26 and June 29 (discussed infra), Dunston
    himself had performed conversion operations and had gotten better
    than a one-to-one yield.            Given that evidence, the court was
    entitled to apply a one-to-one conversion ratio in its appraisal
    of the conspiracy's output.2
    The court also heard the particulars of a transaction
    that occurred on June 29. On that date, the government intercepted
    a call between Hernandez and a third party, during which Hernandez
    bought 200 grams of powder cocaine.            Just over two hours later,
    Dunston called Hernandez to inform him that he planned to "do the
    whole thing together."         He subsequently reported that the result
    was "206 wet," and yellow in color, but quickly turning white.
    Given       this   evidence   and   Boyle's   explanatory    testimony,   the
    district court could have attributed, beyond any reasonable doubt,
    an additional 200 grams of crack to Dunston.                After all, proof
    2
    We note, moreover, that the statute of conviction
    criminalizes conspiracies involving the possession and intended
    distribution of "280 grams or more of a mixture or substance
    . . . which contains cocaine base." 
    21 U.S.C. § 841
    (b)(1)(A)(iii)
    (emphasis supplied).     Whether the weight of the defendants'
    products came from pure crack cocaine or crack combined with water
    or some other adulterant is beside the point: the record reflects
    that the defendants conspired to possess and distribute a "mixture
    or substance" that contained cocaine base. 
    Id.
    - 14 -
    beyond a reasonable doubt does not require proof to an absolute
    certainty.    See United States v. Lasseque, 
    806 F.3d 618
    , 623 (1st
    Cir. 2015), cert. denied, 
    136 S. Ct. 1472
     (2016).
    Dunston counters that the government offered no direct
    or tangible evidence that this batch of cocaine ever existed.       But
    it is old hat that proof of a defendant's guilt can be based, in
    whole or in part, on circumstantial evidence.         See United States
    v. George, 
    841 F.3d 55
    , 63 (1st Cir. 2016); United States v.
    Williams, 
    717 F.3d 35
    , 39-40 (1st Cir. 2013).         In this instance,
    the district court, qua factfinder, drew a series of reasonable
    inferences from the evidence, and its conclusion that Dunston was
    responsible for this additional 200 grams of crack is unimpugnable.
    For these reasons, Dunston's conviction must stand.
    2.   Wooldridge.   The record also provides ample support
    for the district court's decision to attribute at least 280 grams
    of crack cocaine to Wooldridge.            Wooldridge was arrested with
    ninety-three grams of crack on his person.        In addition, there was
    cogent evidence that Wooldridge sold his codefendants the 200 grams
    of powder cocaine mentioned in the June 26 conversation.             As
    explained above, 200 grams of powder could be found, beyond a
    reasonable doubt, to equal 200 grams of crack.              Because the
    production of crack was a reasonably foreseeable act in furtherance
    of the conspiracy, the district court did not err either in finding
    that Dunston and Hernandez converted their shares of the powder
    - 15 -
    sold by Wooldridge into crack or in holding Wooldridge responsible
    for a corresponding amount of crack.      See Sepulveda, 
    15 F.3d at 1197
    .
    In an effort to stave off this conclusion, Wooldridge
    insists that he was not yet part of the charged conspiracy when he
    sold drugs to his codefendants at the end of June.         Building on
    that foundation, he posits that any crack cocaine resulting from
    that sale cannot be attributed to him.            This is revisionist
    history, and we reject it.     Wooldridge pleaded guilty to being a
    member of the conspiracy beginning in August of 2011 — long before
    the sale occurred.    He is bound by his plea.    See United States v.
    Laracuent, 
    778 F.3d 347
    , 351 (1st Cir.), cert. denied, 
    135 S. Ct. 2875
     (2015).
    That ends this aspect of the matter.       We conclude that
    the evidence was sufficient to allow the district court to find
    beyond a reasonable doubt that at least 280 grams of crack were
    attributable to Wooldridge.      Consequently, his conviction must
    stand.
    C.   Dunston's Sentence.
    Dunston's    claim    of   sentencing    error   is   easily
    dispatched.    He does not challenge the district court's guideline
    calculations but, rather, maintains that his 144-month sentence
    offends the parsimony principle, see United States v. Sepúlveda-
    Hernández, 
    817 F.3d 30
    , 34 (1st Cir. 2016) (citing 18 U.S.C.
    - 16 -
    § 3553(a)), because it is greater than necessary to achieve the
    purposes of sentencing.     Under our case law, we treat such a claim
    as one of substantive unreasonableness.      See id.
    Dunston did not raise this claim in the district court,
    and the standard of review is unsettled.        See United States v.
    Ruiz-Huertas, 
    792 F.3d 223
    , 228 (1st Cir.) (noting uncertainty
    with respect to standard of review regarding unpreserved claims of
    substantive   unreasonableness),    cert.   denied,    
    136 S. Ct. 258
    (2015).   For simplicity's sake, we assume — favorably to Dunston
    — that review is for abuse of discretion.
    Dunston was subject to the career offender guideline.
    See USSG §4B1.1(a).    The court below set his guideline sentencing
    range (GSR) at 262-327 months and sentenced him appreciably below
    the bottom of that range.    A defendant who challenges a below-the-
    range sentence as substantively unreasonable must carry a heavy
    burden.   See United States v. Montero-Montero, 
    817 F.3d 35
    , 37
    (1st Cir. 2016).      The greater the drop from the bottom of the
    range, the heavier the lift.     See 
    id.
    There is more than one reasonable sentence in any given
    case, and the relevant inquiry is whether the sentence imposed
    "resides within the expansive universe of reasonable sentences."
    United States v. King, 
    741 F.3d 305
    , 308 (1st Cir. 2014).                In
    mounting this inquiry, we concentrate on whether the sentence
    - 17 -
    reflects "a plausible . . . rationale and a defensible result."
    United States v. Martin, 
    520 F.3d 87
    , 96 (1st Cir. 2008).
    The   court   below   supplied      a    plausible    rationale      for
    Dunston's sentence.        It explained that a significant period of
    incarceration was warranted to protect the public from future
    crimes, provide deterrence, and punish the defendant.                Given the
    scope and duration of the conspiracy, the force of this explanation
    cannot be gainsaid.      The court added, though, that "incarceration
    at or near the advisory guideline range seems to be more than what
    is necessary to meet the goals of sentencing."               For that reason,
    it executed a sharp downward variance.
    Despite the court's seeming leniency, Dunston assails
    the result, arguing that his ultimate sentence was skewed by a
    "mechanical application" of the career offender guideline.                     This
    argument is constructed out of whole cloth: it overlooks the
    undeniable fact that the sentencing court's downward variance was
    anything but mechanical, yielding a sentence almost ten years below
    the nadir of the guideline range.         The challenged sentence, which
    took into account the nature of Dunston's crime, his history, and
    his   personal   characteristics,       was   wholly    defensible       and   well
    within the court's discretion.      See King, 741 F.3d at 309.
    D.    Wooldridge's Sentence.
    Wooldridge      challenges    the       amount   of   crack    cocaine
    attributed to him for sentencing purposes.             This drug quantity (at
    - 18 -
    least 840 grams) is separate from the lesser drug quantity (280
    grams) needed to establish Wooldridge's guilt.                      See supra Part
    IIB.    We explain briefly why two distinct findings are necessary.
    At trial, the government had the burden of proving the
    drug quantity charged as an element of the offense (280 grams or
    more) beyond a reasonable doubt.              See Alleyne, 
    133 S. Ct. at 2155
    .
    At sentencing, however, "a defendant-specific determination of
    drug quantity [i]s a benchmark for individualized sentencing under
    the guidelines."         Colon-Solis, 
    354 F.3d at 103
    .               The sentencing
    court     is     charged      with    making        such   a     defendant-specific
    determination.         See United States v. Correy, 
    773 F.3d 276
    , 279-
    80, 280 n.4 (1st Cir. 2014).                  All drugs "attributable to[] or
    reasonably foreseeable by" a defendant may be included in that
    defendant's      individualized       total.        United      States   v.   Cintrón-
    Echautegui, 
    604 F.3d 1
    , 5 (1st Cir. 2010).                     The government bears
    the     burden    of    proving      drug     quantity     at    sentencing      by    a
    preponderance of the evidence.               See 
    id. at 6
    .
    The sentencing guidelines direct a sentencing court to
    consider relevant conduct, see USSG §1B1.3(a), when assessing the
    drug quantity for which a defendant is to be held accountable at
    sentencing.       Where, as here, a defendant has been convicted as a
    coconspirator, his relevant conduct includes not only his own acts
    and    omissions       but   also    the    reasonably     foreseeable        acts    and
    - 19 -
    omissions     of   other      coconspirators    in    furtherance      of     the
    conspiracy.    See id. §1B1.3(a)(1)(B).
    A sentencing determination of defendant-specific drug
    quantity does not require mathematical precision: it need only be
    a   "reasonable    approximation    of   the   weight     of   the   controlled
    substance(s) for which the defendant should be held responsible."
    United States v. Demers, 
    842 F.3d 8
    , 12 (1st Cir. 2016).                    As we
    have said, calculating drug quantities "is not an exact science,"
    and the sentencing court "need not be precise to the point of
    pedantry."     United States v. Platte, 
    577 F.3d 387
    , 392 (1st Cir.
    2009).
    Such drug-quantity determinations are quintessentially
    factual in nature, and we review them for clear error.                        See
    Cintrón-Echautegui, 
    604 F.3d at 6
    .           That standard dictates that a
    finding will stand unless a reviewing court, after assessing the
    whole of the record, is firmly convinced that a mistake has been
    made.    See 
    id.
       "[W]here there is more than one plausible view of
    the circumstances, the sentencing court's choice among supportable
    alternatives cannot be clearly erroneous."           United States v. Ruiz,
    
    905 F.2d 499
    , 508 (1st Cir. 1990).
    Against   this    backdrop,     Wooldridge    argues     that    the
    district court committed clear error in finding him accountable
    for at least 840 grams of crack cocaine.             That finding, combined
    with other uncontroversial guideline calculations and Wooldridge's
    - 20 -
    designation as a career offender, see USSG §4B1.1(a), resulted in
    a GSR of 262-327 months.    The district court proceeded to impose
    a below-the-range sentence of 132 months.
    Although the district court varied downward from the
    guideline range, any error in calculating that range would likely
    be material on appeal.   See Molina-Martinez v. United States, 
    136 S. Ct. 1338
    , 1346 (2016) ("In most cases a defendant who has shown
    that the district court mistakenly deemed applicable an incorrect,
    higher Guidelines range has demonstrated a reasonable probability
    of a different outcome.").    Here, however, the district court's
    drug-quantity determination (and, thus, its configuration of the
    GSR) is not clearly erroneous.
    The district court identified three transactions that
    linked Wooldridge to well over 840 grams of crack cocaine.   First,
    Wooldridge sold powder cocaine to Hernandez and Dunston at the end
    of June and, as discussed above, see supra Part IIB, that sale
    formed a solid basis for a finding attributing approximately 200
    grams of crack cocaine to him.   Second, the court supportably tied
    Wooldridge to a purchase of 300 grams of powder cocaine that
    occurred on July 31.3    The record includes discussions among all
    three defendants about the purchase and about their plans to
    3 Indeed, Wooldridge admits that the ninety-three grams of
    crack cocaine found on his person when he was arrested was his
    share of this purchase.
    - 21 -
    convert the powder into crack.        That evidence, coupled with the
    court's permissible use of a one-to-one conversion ratio, was
    sufficient to ground attribution of 300 grams of crack cocaine to
    Wooldridge.
    Third, and finally, the court reasonably attributed an
    additional 497 grams of crack cocaine to Wooldridge with respect
    to events occurring on August 31.          At that time, federal agents
    seized a package sent by Cruz (in Puerto Rico) to an acquaintance
    of Hernandez (in Massachusetts).      The package was found to contain
    497 grams of powder cocaine.      Although the evidence indicated that
    Hernandez was the prime mover in arranging for the shipment, both
    Wooldridge and Dunston encouraged his efforts. Thus, the 497 grams
    of powder cocaine, destined for conversion into crack cocaine,
    could fairly be attributed to Wooldridge for sentencing purposes.
    See Cintrón-Echautegui, 
    604 F.3d at 5
    ; USSG §1B1.3(a)(1)(B).
    The fact that the package was intercepted before its
    contents reached the defendants is of no moment.         The record makes
    manifest that the defendants, in furtherance of the conspiracy,
    sought the shipment of powder cocaine as a prelude to conversion
    and would in all probability have converted it to crack cocaine if
    given the chance.       Indeed, the government introduced evidence
    showing that, on no fewer than seven separate occasions between
    June   and   August,   the   defendants    procured   powder   cocaine   and
    converted it into crack cocaine within a matter of days.                 When
    - 22 -
    drug traffickers have forged a well-defined pattern and practice
    for their operations, a sentencing court need not turn a blind eye
    to that pattern and practice.
    Wooldridge tries to distance himself from this drug
    weight, asseverating that no part of the August 31 shipment should
    be attributed to him because his coconspirators had "cut[] [him]
    out of the picture" by then.        But the evidence of exclusion is
    meager, and the district court was not obliged to resolve this
    issue in Wooldridge's favor.      Just as withdrawal from a conspiracy
    requires more than an empty claim of disaffection, see United
    States v. Piper, 
    298 F.3d 47
    , 53 (1st Cir. 2002) (explaining that,
    in order to withdraw, a conspirator must take affirmative action
    to disavow or defeat the conspiracy), so too does a claim of
    exclusion.      There is simply no credible evidence that either
    Wooldridge or his partners in crime took any such action here.         To
    the   contrary,   the   record   reflects   that   Wooldridge   contacted
    Hernandez at the end of July in search of cocaine and exhibited an
    abiding intent to remain involved in the conspiracy.            Given the
    absence of any competent evidence of withdrawal, the sentencing
    court did not clearly err in finding the coconspirators' acts at
    the end of August to be a part of Wooldridge's relevant conduct.
    E.   Hernandez's Sentence.
    Hernandez's claim of sentencing error similarly embodies
    a challenge to the district court's drug-quantity determination.
    - 23 -
    The court found him responsible for at least 2.8 kilograms of crack
    cocaine.           Combined      with     other     uncontroversial        guideline
    calculations and a career offender enhancement, this drug quantity
    resulted in a GSR of 292-365 months.                 The district court imposed
    a below-the-range sentence of 162 months.
    The record is replete with circumstantial evidence that
    Hernandez headed up the conspiracy.                   He was involved in every
    transaction that we have discussed: the events of June 26 (200
    grams), the events of June 29 (200 grams), the events of July 31
    (300   grams),      and    the   events    of     August   31   (497    grams).      In
    consequence of this involvement, 1,197 grams of crack cocaine were
    fairly attributable to him.
    Furthermore, the record contains proof sufficient to
    support      the    attribution      to     Hernandez,      using      a   one-to-one
    conversion ratio, of an additional 1,000 grams of crack cocaine:
        200 grams of powder cocaine purchased and converted on July
    7;
        100 grams of powder cocaine converted on July 15;
        500   grams    of    powder      cocaine    purchased    on     August   5   and
    converted the following day; and
        200 grams of powder cocaine purchased on August 28 and at
    least partially converted the next day.
    When these quantities are combined with the nearly forty-four grams
    of crack sold by Hernandez to undercover officers at the start of
    - 24 -
    the probe, Hernandez can properly be held responsible for a minimum
    of 2.2 kilograms of crack cocaine.
    To boost that total to 2.8 kilograms, the district court
    reasonably relied on two additional events.                 First, the evidence
    showed that, on July 29, Hernandez arranged the payment of $19,000
    to   Cruz       for   powder   cocaine    previously     supplied.      The   court
    supportably concluded that this payment represented the purchase
    of roughly 500 grams of powder cocaine.                See Sepulveda, 
    15 F.3d at 1201
     (holding that when cash is likely dedicated to the purchase
    of contraband, "a sentencing court may convert the cash into
    equivalent amounts of narcotics" for sentencing purposes).                    After
    applying a one-to-one conversion ratio, this transaction yielded
    500 grams of crack cocaine attributable to Hernandez.
    The court reasonably added another 100 grams, based on
    evidence that Hernandez was actively dealing crack cocaine between
    January and June (when the wiretaps were instituted).                  While this
    finding represented an estimate, it was by all odds a conservative
    estimate — especially since Hernandez pleaded guilty to conspiring
    to deal crack as early as August of 2011.                  We have consistently
    upheld      a    sentencing    court's    use     of   reasonable    estimates   in
    assessing drug quantity, see, e.g., United States v. Bernier, 
    660 F.3d 543
    , 546 (1st Cir. 2011); Platte, 
    577 F.3d at 392
    ; United
    States v. Ventura, 
    353 F.3d 84
    , 88 (1st Cir. 2003), and that praxis
    has particular appeal when — as in this case — the sentencing
    - 25 -
    court,   in    fashioning   its   estimate,    has   taken   a   conservative
    approach, cf. United States v. Sklar, 
    920 F.2d 107
    , 113 (1st Cir.
    1990) (admonishing sentencing courts, in this context, to "err on
    the side of caution" (citation omitted)).
    This gets the grease from the goose.           While we could
    analyze these multiple transactions in more granular detail, doing
    so would serve no useful purpose.            It suffices to say that the
    record discloses ample evidence to ground a finding that Hernandez
    was responsible for at least 2.8 kilograms of crack cocaine.              As
    a result, we discern no clear error in the district court's drug-
    quantity determination.
    Hernandez has one last string to his bow. He takes issue
    with the district court's designation of him as a career offender
    under the sentencing guidelines.            Specifically, he asserts that
    the court improperly relied, over objection, on a portion of his
    presentence      investigation    report,    which   cited   only   criminal
    offender record information (CORI) to lay out his criminal history.
    The government bears the burden of establishing the
    existence of at least two predicate offenses to trigger a career
    offender enhancement under the sentencing guidelines.             See United
    States v. Bryant, 
    571 F.3d 147
    , 153 (1st Cir. 2009) (citing USSG
    §4B1.1(a)).      The government may carry this burden in divers ways,
    such as by furnishing "a certified copy of the conviction or an
    equivalent proffer" or by pointing to official court documents of
    - 26 -
    the type that engender a presumption of reliability.            Id. at 153,
    155 (quoting United States v. McKenzie, 
    539 F.3d 15
    , 19 (1st Cir.
    2008)).     But anecdotal CORI descriptions, if objected to, are not
    enough.     See 
    id. at 154-55
    ; cf. United States v. Brown, 
    510 F.3d 57
    , 74 (1st Cir. 2007) (observing that "when a defendant challenges
    a conviction laid out in the [presentence investigation report],
    more is required").
    At Hernandez's sentencing, the government argued for a
    career    offender   enhancement    noting   that     the   CORI    material
    described in the presentence investigation report identified three
    potential predicate offenses.       Hernandez objected.       The district
    court stayed the proceedings to give the government the opportunity
    to make a more persuasive evidentiary proffer; but when the
    government produced nothing more, the court overruled Hernandez's
    objection and sentenced him as a career offender.
    On appeal, Hernandez insists that the record before the
    district court was insufficient to show the required predicate
    offenses.    The government concedes this point and instead proffers
    a series of docket sheets, never made available to the district
    court, inviting us to take judicial notice of them.           These docket
    sheets, it says, will confirm the existence of the required
    predicate     offenses   (albeit   belatedly)   and    render      any   error
    harmless.
    - 27 -
    We decline the government's invitation.          As a general
    matter, we do not consider evidentiary materials that were not
    proffered in the district court.             See United States v. Farrell,
    
    672 F.3d 27
    , 30-31 (1st Cir. 2012); United States v. Kobrosky, 
    711 F.2d 449
    , 457 (1st Cir. 1983). Although we have occasionally taken
    judicial notice of state court documents identified for the first
    time on appeal, see, e.g., Farrell, 
    672 F.3d at 31
    ; United States
    v. Mercado, 
    412 F.3d 243
    , 247-48 (1st Cir. 2005), we cannot do so
    here.   The proffered documents bear no hallmarks of authenticity
    and, in all events, are subject to interpretation.                  A career
    offender designation can expose a defendant to a significantly
    higher sentence, and it remains the district court's duty to ensure
    that documents offered to prove the existence of predicate offenses
    are "sufficiently reliable."       Bryant, 
    571 F.3d at 154
    .
    Although we conclude that the district court erred, we
    think   it    would   be   premature   to    vacate   Hernandez's   sentence.
    Instead, we remand so that the district court may hold a hearing
    and afford the parties an opportunity to present evidence anent
    Hernandez's prior convictions.          Should the district court find
    that    the    evidence    presented    is     sufficiently   reliable    and
    establishes the existence of the requisite number of predicate
    offenses, it should, within sixty days from the date hereof, report
    its findings and conclusions to this court. If, however, the court
    finds to the contrary, it should, within sixty days from the date
    - 28 -
    hereof, report its findings and conclusions to this court and
    proceed to vacate Hernandez's sentence and resentence him without
    reference to the career offender guideline.
    III.   CONCLUSION
    We need go no further. For the reasons elucidated above,
    we affirm the judgment in appeal number 15-1812, thus affirming
    Dunston's conviction and sentence. We likewise affirm the judgment
    in appeal number 15-2000, thus affirming Wooldridge's conviction
    and sentence.   With respect to appeal number 15-1999 (Hernandez),
    we remand for further proceedings consistent with this opinion and
    for the time being retain appellate jurisdiction over this appeal.
    So ordered.
    - 29 -