NOT RECOMMENDED FOR PUBLICATION

File Name: 21a0333n.06

No. 20-1630

UNITED STATES COURT OF APPEALS

FOR THE SIXTH CIRCUIT

UNITED STATES OF AMERICA,

Plaintiff–Appellee,

v.

ANTHONY MICHAEL ASSFY,

Defendant–Appellant.

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ON APPEAL FROM THE 

UNITED STATES DISTRICT 

COURT FOR THE WESTERN

DISTRICT OF MICHIGAN

OPINION

Before: SILER, MOORE, and THAPAR, Circuit Judges.

KAREN NELSON MOORE, Circuit Judge. This case starkly presents the tragedy of 

the ongoing opioid crisis. In the early morning hours on August 29, 2018, Defendant Anthony 

Assfy sold what he thought was heroin to Daniel Coon. Later that day, Coon overdosed on 

methadone and fentanyl and died shortly thereafter. Investigations by local and federal law 

enforcement identified Assfy as the dealer who last sold narcotics to Coon as well as a dealer 

involved in several other drug deals. Subsequently, a federal grand jury indicted Assfy on several 

counts of drug possession and distribution offenses, including for selling Coon the fentanyl that 

resulted in Coon’s death. A jury found Assfy guilty on all counts. Assfy now challenges the 

sufficiency of the evidence supporting the jury’s verdict as well as various rulings that the district 

court made over the course of his trial. We AFFIRM.
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I. BACKGROUND

The events that precipitated this case began late in the evening on August 28, 2018. At 

around 11:00 p.m., Assfy and Coon engaged in a series of text messages, setting up a drug deal. 

Coon asked Assfy to deliver $100 worth of narcotics, split into two packages, to Coon’s workplace. 

R. 112 (Trial Tr. Vol. I, Hansen Test. at 168–70) (Page ID #1741–43). At around 1:00 a.m. on

August 29, Assfy delivered the drugs to Coon’s car. Id. at 169–70 (Page ID #1742–43). Several 

hours later, at approximately 10:00 p.m., the local fire department responded to an emergency call 

from Coon’s residence and found him deceased in his basement from what appeared to be a drug 

overdose. R. 112 (Trial Tr. Vol. I, Tuinhoff Test. at 124–27) (Page ID #1697–1700). A medical 

examiner later determined that Coon died eight to twelve hours before emergency services arrived. 

R. 106 (Trial Tr. Vol. III, Cohle Test. at 25) (Page ID #636). The medical examiner also concluded 

that an extreme level of fentanyl, coupled with a high level of methadone, caused Coon’s death. 

Id. at 20, 28, 31 (Page ID #631, 639, 642).

Law enforcement immediately began investigating Coon’s death. Using Coon’s cell 

phone, Detective Warren Hansen identified a likely source of the narcotics that appeared to have 

caused Coon’s death. R. 112 (Trial Tr. Vol. I, Hansen Test. at 162–63) (Page ID #1735–36). 

Hansen, pretending to be Coon, set up a controlled buy for the next day with the last narcotics 

dealer with whom Coon texted before his death, requesting the same amount of drugs at the same 

drop-off location. Id. at 171–76 (Page ID #1744–49). On August 30, Assfy showed up at the 

drop-off location and attempted to leave drugs in what he believed was Coon’s car. Id. at 177 

(Page ID #1750). Law enforcement arrested him on the spot. Subsequent searches after the arrest 

revealed fentanyl in Assfy’s vehicle and fentanyl and crack cocaine on his person, as well as a cell 
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phone with the text messages that matched the conversations between Assfy and Coon found on 

Coon’s phone. R. 111 (Trial Tr. Vol. II, Hansen Test. at 16) (Page ID #1406); R. 111 (Trial Tr. 

Vol. II, Giudice Test. at 138, 140) (Page ID #1528, 1530). Although Coon’s text messages 

reflected that he dealt marijuana and had several other sources for acquiring drugs, law 

enforcement determined that the last narcotic transaction Coon completed before his death was 

with Assfy. R. 111 (Trial Tr. Vol. II, Hansen Test. at 24–25, 28, 51) (Page ID #1414–15, 1418, 

1441). Detective Hansen also interviewed Assfy after the arrest, and Assfy admitted to selling 

drugs to Coon at least four or five times. R. 112 (Trial Tr. Vol. I, Hansen Test. at 184) (Page ID 

#1757).

After being released on bond, Assfy continued selling drugs, including three controlled 

buys to a confidential informant, which resulted in law enforcement arresting him again. R. 111 

(Trial Tr. Vol. II, Woollam Test. at 96, 111) (Page ID #1486, 1501). A federal grand jury then 

indicted Assfy on the following six counts: (1) distribution of fentanyl, which resulted in the death

of Coon on August 29, 2018, (2) possession with intent to distribute fentanyl and cocaine base on 

August 30, 2018, (3) distribution of heroin and cocaine base on October 2, 2018, (4) distribution 

of heroin and cocaine base on October 25, 2018, (5) distribution of heroin and cocaine base on 

November 12, 2018, and (6) possession with intent to distribute heroin and cocaine base on 

November 13, 2018. R. 1 (Indictment at 1–6) (Page ID #1–6). Assfy initially pleaded not guilty 

and proceeded to trial.

Before trial, Assfy filed a motion in limine, seeking to prohibit one of the government’s 

expert witnesses, Agent Thomas Burns, from testifying. Assfy argued that Agent Burns’s 

testimony focused on discussing common drug-trafficking practices and interpreting “drug lingo”
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and that such testimony would not be reliable, nor would it be helpful to the jury. R. 50 (Def.’s 

Mot. in Lim. at 1–4, 11) (Page ID #149–52, 159). The district court disagreed, noting that the 

Sixth Circuit recently affirmed the admission of “testimony from Agent Burns on similar topics in 

another distribution resulting in death case,” and that the government would be able to establish 

the necessary foundation to qualify Agent Burns as an expert witness. R. 67 (Mot. in Lim. Order 

at 1–3) (Page ID #278–80).

The Friday before the trial was to begin, Assfy attempted to plead guilty to counts three 

through six of the indictment. The district court denied Assfy’s request. The district court 

determined that “[e]ven if Counts 3 through 6 were somehow removed from the jury by 

Defendant’s guilty plea, the scope of the government’s evidentiary proofs on the remaining counts 

would probably remain about the same,” reasoning that Assfy’s conduct “could still be relevant, 

for example, in establishing his intent to distribute” for the remaining counts. R. 77 (Sealed Order 

at 2) (Page ID #365). The district court also noted that counts three through six contained similar 

types of conduct as counts one and two, and the conduct at issue was not “highly inflammatory.” 

Id. Prior to proceeding with the trial, the district court allowed both parties to state their positions 

as to whether the court should accept Assfy’s partial plea. R. 112 (Trial Tr. Vol. I at 4–10) (Page 

ID #1577–83). After hearing both parties’ arguments, the district adhered to its original order. Id.

at 9 (Page ID #1582). Assfy proceeded to trial on all six counts.

A jury found Assfy guilty on all counts. R. 85 (Verdict) (Page ID #375). Assfy 

subsequently filed a motion for acquittal under Federal Rule of Criminal Procedure 29 and a 

motion for a new trial under Rule 33. The district court denied both motions. The case proceeded 

to sentencing, and the district court sentenced Assfy to 240 months’ imprisonment to be served 
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concurrently for all six counts. R. 100 (Judgment at 3) (Page ID #540). Assfy timely appealed, 

challenging the jury’s verdict as well as various rulings the district court made over the course of 

his trial.

II. ANALYSIS

On appeal, Assfy raises three sets of issues: (A) evidentiary issues, (B) plea issues, and 

(C) sufficiency-of-proof issues. We address each in turn.

A. Admission of Expert Testimony

Assfy contends that the district court erred in permitting Agent Burns to offer unreliable 

testimony concerning the common practices of drug traffickers and opinion testimony about the 

meaning of certain “plain English” drug-trafficking phrases. We review a district court’s decision 

to admit evidence as expert testimony for an abuse of discretion. United States v. Lopez-Medina, 

461 F.3d 724, 741 (6th Cir. 2006).

Under Federal Rule of Evidence 702, a witness with “specialized knowledge” qualified by 

his or her “knowledge, skill, experience, training, or education” may give “expert” opinion 

testimony if it “will help the trier of fact to understand the evidence or to determine a fact in issue.” 

FED. R. EVID. 702. District courts must ensure that any expert testimony is both relevant, i.e., aids 

the jury in understanding evidence or determining a fact in issue, and reliable. Kumho Tire Co. v. 

Carmichael, 526 U.S. 137, 147 (1999). Rule 702 affords district courts “considerable leeway in 

deciding in a particular case how to go about determining whether particular expert testimony is 

reliable.” Id. at 152. In the law-enforcement context, we routinely hold that testimony concerning

the “common practices of the drug trade,” including the translation of drug-trafficking vernacular 

used by other witnesses, is both relevant and reliable expert testimony when given by experienced 
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law-enforcement agents. United States v. Maya, 966 F.3d 493, 505 (6th Cir. 2020) (collecting 

cases).

The district court did not abuse its discretion in finding that Agent Burns’s testimony was 

both relevant and reliable. Agent Burns’s testimony focused on the common practices of narcotics 

distribution and drug trafficking generally. He also translated several examples of drug-trafficking 

“code” for the jury, including the terms “boy,” “girl,” “smoke,” and “bars.” R. 111 (Trial Tr. Vol. 

II, Burns Test. at 165–66) (Page ID #1555–56). As mentioned earlier, we consistently have 

concluded that such translation services are relevant and assist jurors in understanding text 

messages and other communications exchanged between dealers and their customers, like Assfy 

and Coon. See, e.g., United States v. Whyte, 795 F. App’x 353, 360–61 (6th Cir. 2019) (permitting

Agent Burns to offer his expert opinion on the meaning of “drug trafficking jargon” such as “hot,” 

“cut,” and “the trap”). Moreover, despite Assfy’s contention, Agent Burns’s testimony was also 

reliable: Agent Burns testified to having almost thirty years of Drug Enforcement Administration 

(“DEA”) experience, extensive training in drug investigations, and almost fifteen years of 

experience working with local law-enforcement teams conducting drug investigations in 

Michigan. R. 111 (Trial Tr. Vol. II, Burns Test. at 160–62) (Page ID #1550–52). See LopezMedina, 461 F.3d at 742–43 (holding that agents with seventeen years and six years, respectively, 

of DEA employment and other experience and training in narcotics investigations were reliable 

expert witnesses on drug-trafficking practices). Accordingly, the district court did not abuse its 

discretion in admitting Agent Burns’s testimony.
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B. Denial of Partial Guilty Plea

We review a district court’s decision to reject a guilty plea for an abuse of discretion. 

United States v. Doggart, 906 F.3d 506, 509 (6th Cir. 2018). Although criminal defendants do not 

have an absolute constitutional right to plead guilty, “a district court must provide a sound reason 

for refusing a plea.” Id.; see also Santobello v. New York, 404 U.S. 257, 262 (1971).

Assfy argues that the district court erred in denying his partial guilty plea. As a result,

Assfy contends that the district court allowed the government to present “irrelevant and highly 

prejudicial evidence” that would have been inadmissible had the court accepted the partial plea. 

Appellant Br. at 20. We addressed this same argument in a recent unpublished decision, United 

States v. Simpson, 845 F. App’x 403 (6th Cir. 2021). There we held that the district court did not 

abuse its discretion in rejecting the defendant’s request to accept his partial guilty plea. The district 

court denied the request for three reasons: (1) the admissible evidence would have been the same 

regardless of whether the defendant pleaded guilty, (2) if the defendant pleaded guilty, he likely

would have made “unfavorable admissions” during the plea colloquy that “would presumptively 

be considered admissible evidence,” and (3) the defendant could have stipulated during his 

opening statement that he was not contesting guilt for certain counts. Id. at 409. We concluded 

that these constituted sound reasons for rejecting the partial plea and upheld the district court’s 

decision. Id.

The district court in the instant case provided similar reasons for denying Assfy’s request 

to plead guilty to certain counts. First, the district court stated that it was not “aware of [any] 

authority that would require it to accept a guilty plea well after the Final Pretrial Conference was 

held and on the eve of trial.” R. 77 (Sealed Order at 2) (Page ID #365). Second, the district court 
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also found that Assfy would not suffer any prejudice from the denial because the government’s 

evidence would likely remain the same, the conduct to which Assfy wanted to plead guilty was

similar to the remaining two counts and was not “highly inflammatory,” the government could still 

use the defendant’s statements during the plea colloquy as evidence, and Assfy could concede 

certain facts or charges without pleading guilty. Id. at 2–3 (Page ID #365–66); R. 112 (Trial Tr. 

Vol. I at 9–10) (Page ID #1582–83). Assfy has not identified any binding Sixth Circuit precedent 

that indicates that the district court’s reasons would or would not constitute sound reasons for 

declining to accept his late partial guilty plea.

Assfy, however, raises one argument that we did not address in Simpson. Relying on two 

out-of-circuit cases, Assfy contends that the district court lacked any discretion to reject his 

“straight up” guilty plea that did not include a plea agreement because Assfy’s plea satisfied the 

requirements of Federal Rule of Criminal Procedure 11(b). Appellant Br. at 22–25; In re VasquezRamirez, 443 F.3d 692, 695–96 (9th Cir. 2006) (“[V]iewing Rules 11(a) and (b) together, it is clear 

that a court must accept an unconditional guilty plea, so long as the Rule 11(b) requirements are 

met. The existence or non-existence of a Rule 11(c) plea agreement is irrelevant to the separate 

issue of how a defendant chooses to plead.”); United States v. Martin, 528 F.3d 746, 750 (10th 

Cir. 2008) (citing Vasquez-Ramirez, 443 F.3d at 695–96) (doubting that a “district court’s desire 

to avoid confusing the jury or complicating the evidentiary issues was a sufficient basis for 

rejecting the partial plea,” but affirming its decision due to the lack of a factual basis for the plea

as required by Rule 11(b)(3)). In Vasquez-Ramirez, the Ninth Circuit astutely noted that although 

many courts cite to Santobello for the “‘well-settled proposition that a defendant has no absolute 

right . . . to have his guilty plea accepted,’ . . . . Santobello was decided before 1975, when Rule 
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11 was amended to remove the language that explicitly gave courts the ability to reject a guilty 

plea.” Vasquez-Ramirez, 443 F.3d at 700 n.9 (alteration in original) (quoting United States v. 

Gomez-Gomez, 822 F.2d 1008, 1010 (11th Cir. 1987). In reaching its holding that district courts 

must accept an unconditional guilty plea when the plea meets Rule 11(b)’s requirements, the Ninth 

Circuit also cited United States v. Maddox, 48 F.3d 555, 559–60 (D.C. Cir. 1995), where the D.C. 

Circuit held that “a district court abused its discretion by rejecting a guilty plea without regard for 

whether the Rule 11(b) requirements had been met.” Vasquez-Ramirez, 443 F.3d at 700. Taken 

together, these cases persuasively suggest that the district court in this case abused its discretion 

by rejecting Assfy’s partial guilty plea without ever conducting a hearing or colloquy to ascertain 

whether his partial guilty plea would satisfy Rule 11(b)’s requirements.

Even if we decide that these out-of-circuit cases persuade us to disagree with our 

unpublished decision in Simpson, we hold that the district court’s error was harmless. We agree 

with the district court’s determination that it more than likely would have admitted the evidence 

concerning counts three through six, regardless of whether Assfy pleaded guilty to those counts

because the government still needed to prove Assfy’s specific intent to distribute controlled 

substances for counts one and two. And we have held that subsequent acts of drug distribution, 

like counts three through six at issue here, may be admissible under Federal Rule of Evidence 

404(b) to prove a specific intent offense at issue in a trial, such as the count of possession with 

intent to distribute to which Assfy did not agree to plead guilty. See United States v. Barnes, 822 

F.3d 914, 920–24 (6th Cir. 2016); see also United States v. Johnson, 27 F.3d 1186, 1192–93 (6th 

Cir. 1994) (When a defendant does not plead guilty and the government has “the affirmative duty 

to prove that the underlying prohibited act was done with a specific criminal intent, other acts
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evidence may be introduced under Rule 404(b)”).1 Consequently, we conclude that were we to 

hold that, in accordance with Vasquez-Ramierz, the district court abused its discretion by rejecting 

Assfy’s partial guilty plea, that ruling did not materially affect the verdict and therefore was 

harmless. See Whyte, 795 F. App’x at 359–60 (discussing the harmless-error rule).2

C. Sufficiency of Proof

We review de novo challenges to the sufficiency of evidence. United States v. Ray, 803 

F.3d 244, 262 (6th Cir. 2015). However, “[w]hen reviewing for the sufficiency of evidence in 

support of a jury verdict, . . . we view the evidence in the light most favorable to the government 

and give the government the benefit of all reasonable inferences from the testimony”; we do “not 

‘weigh the evidence, consider the credibility of witnesses or substitute our judgment for that of the 

jury.’” Id. (quoting United States v. Hilliard, 11 F.3d 618, 620 (6th Cir. 1993)). Accordingly, if 

“any rational trier of fact could have found the essential elements of the crime beyond a reasonable 

doubt,” we must uphold the jury’s verdict. Jackson v. Virginia, 443 U.S. 307, 319 (1979). Assfy 

has not overcome this heavy burden.

Federal law imposes enhanced penalties on persons who knowingly distribute a controlled 

substance that then results in a user’s death. 21 U.S.C. § 841(b)(1)(C); Burrage v. United States, 

1

In his opening statement, Assfy’s counsel focused exclusively on the “resulting in death” count (count one) 

but never explicitly conceded counts two through six. R. 112 (Trial Tr. Vol. I at 118–21) (Page ID #1691–94). 

Because “[i]t is not entirely clear whether, by reason of his counsel’s opening statement to the jury,” Assfy “placed in 

issue the intent to distribute component of the offense with which he [was] charged,” the government still had the duty 

to prove Assfy’s specific intent to distribute for count two. Johnson, 27 F.3d at 1193.

2Although Assfy does not argue that the rejected partial plea prejudiced his sentencing, we note that any error 

in rejecting the plea also would be harmless error as it relates to Assfy’s sentence because we have held that partial

guilty pleas do not entitle a defendant to a reduction in sentence for acceptance of responsibility. United States v. 

Chambers, 195 F.3d 274, 278–79 (6th Cir. 1999). Furthermore, the district court considered Assfy’s willingness to 

plead guilty to certain counts when determining his sentence. R. 108 (Sentencing Hr’g Tr. at 28–29) (Page ID #780–

81). Accordingly, Assfy did not suffer any prejudice during sentencing from the denied partial guilty plea.
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571 U.S. 204, 206 (2014). To prove that a particular distribution resulted in a user’s death, the 

government must show that the distribution was “either an independent, sufficient cause of the 

victim’s death or a but-for cause.” United States v. Allen, 716 F. App’x 447, 450 (6th Cir. 2017). 

“But-for causation” occurs when the distributed drug “‘combines with other factors to produce’ 

death, and death would not have occurred ‘without the incremental effect’ of the controlled 

substance.” United States v. Volkman, 797 F.3d 377, 392 (6th Cir. 2015) (quoting Burrage, 

571 U.S. at 211).

Sufficient evidence exists to uphold the jury’s verdict. A rational jury could have found 

that the drugs Coon used on August 29 were the drugs that Assfy distributed to Coon earlier that 

morning. Text messages, video evidence, and other records revealed that Assfy distributed drugs 

to Coon early in the morning on August 29. R. 111 (Trial Tr. Vol. II, Hansen Test. at 6–14, 24) 

(Page ID #1396–1404, 1414); R. 112 (Trial Tr. Vol. I, Hansen Test. at 168–77) (Page ID #1741–

50). Later that night, after Coon’s death, the police, using Coon’s cell phone, set up another buy

for the very next day with Assfy, asking Assfy to drop off the same amount of drugs at the same 

location. Id. at 171–76 (Page ID #1744–49). When Assfy attempted to drop off the drugs, the

police arrested him and found what they later ascertained to be fentanyl and cocaine base in his 

car and on his person. R. 111 (Trial Tr. Vol. II, Hansen Test. at 16) (Page ID #1406). Although 

Assfy thought he was selling heroin, a rational jury could find that he was unknowingly selling the 

much stronger fentanyl. See United States v. Davis, 970 F.3d 650, 658 (6th Cir. 2020). Detective 

Hansen testified that Assfy’s drugs were not the same color that heroin normally appears. R. 112 

(Trial Tr. Vol. I, Hansen Test. at 187–88) (Page ID #1760–61). And text messages confirmed that 

Assfy’s customers noted that the batch of drugs he was selling at or around the end of August was 
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a much stronger batch than normal. R. 111 (Trial Tr. Vol. II, Giudice Test. at 154) (Page ID 

#1544). Furthermore, a rational jury could have found that Coon’s death “result[ed] from [his]

use of” Assfy’s drugs. 21 U.S.C. § 841(b)(1)(C). Both medical experts testified that fentanyl was 

a sufficient independent cause of Coon’s death, and the government’s expert found that the 

methadone found in Coon’s system was not by itself the cause of Coon’s death. R. 106 (Trial Tr. 

Vol. III, Cohle Test. at 30–31) (Page ID #641–42); R. 106 (Trial Tr. Vol. III, Judge Test. at 46–

47) (Page ID #657–58). Dr. Stephen Cohle, the medical examiner, also testified that Coon would 

have taken the fentanyl and methadone separately; Coon would have injected the fentanyl and 

orally consumed the methadone. R. 106 (Trial Tr. Vol. III, Cohle Test. at 22, 35) (Page ID #633, 

646). The evidence adequately establishes both requirements of the § 841(b)(1)(C) enhancement. 

See United States v. Simer, 835 F. App’x 60, 65 (6th Cir. 2020) (noting that “‘[c]ircumstantial 

evidence alone is sufficient to sustain a conviction,’ as ‘such evidence need not remove every 

reasonable hypothesis except that of guilt’” (alteration in original) (quoting United States v. Peters, 

15 F.3d 540, 544 (6th Cir. 1994))).

Assfy’s sole contention on appeal is that no rational juror could have found that the drugs 

he sold Coon caused Coon’s death. Specifically, he argues that the time that elapsed between the 

sale and Coon’s death plus Coon’s known other drug dealings point to some other unidentified

dealer as the source of the fentanyl that killed Coon. We typically reject these types of sufficiency 

arguments as they are “speculative possibilities already rejected by the jury.” Id. at 65–66; see 

also Whyte, 795 F. App’x at 364. Moreover, the detectives who searched Coon’s phone 

determined that Coon did not deal in narcotics. R. 111 (Trial Tr. Vol. II, Hansen Test. at 51) (Page 

ID #1441); R. 111 (Trial Tr. Vol. II, Giudice Test. at 159) (Page ID #1549). Detective Hansen 
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also testified that the last narcotic transaction that Coon completed was with Assfy. R. 111 (Trial 

Tr. Vol. II, Hansen Test. at 24–25, 44, 51) (Page ID #1414–15, 1434, 1441). Thus, the jury had 

sufficient evidence from which to conclude that Assfy was the source of the fentanyl that resulted 

in Coon’s death.

Assfy’s reliance on our decision in United States v. Ewing is not persuasive. 749 F. App’x 

317 (6th Cir. 2018). In Ewing, the evidence showed that the defendant sold the victim fentanyl 

laced with heroin but there was no trace of heroin in the victim’s system. Id. at 329. Because the 

victim “clearly had access to other illicit substances” in the period before his death, which the 

government did not attribute to the defendant, and the government did not put forth any evidence 

to explain the absence of heroin in the victim’s blood, we concluded that the jury’s verdict 

regarding the enhancement was not supported by sufficient evidence. Id. at 330. Here, however, 

there is no such “unexplained gap in the evidence.” Id. at 329. As discussed above, the 

government put forth enough evidence for a rational juror to conclude that (1) Assfy unknowingly 

sold fentanyl to Coon, (2) Assfy was the last person to sell narcotics to Coon, and (3) Coon died 

from a fentanyl overdose. Unlike in Ewing, there was no evidence that Assfy sold Coon fentanyl 

that was laced with a drug that did not appear in his blood. Consequently, we reject Assfy’s 

challenge to the sufficiency of the evidence.

III. CONCLUSION

For reasons explained above, we AFFIRM Assfy’s convictions.