United States Court of Appeals

For the Eighth Circuit

___________________________

No. 23-3255

___________________________ 

United States of America

 Plaintiff - Appellee

v.

Tommy Collier

 Defendant - Appellant

____________

Appeal from United States District Court 

for the Eastern District of Arkansas - Central

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Submitted: April 9, 2024

Filed: September 6, 2024

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Before SMITH, WOLLMAN, and GRASZ, Circuit Judges.

____________

SMITH, Circuit Judge.

A jury found Tommy Collier guilty of unlawfully possessing cocaine with 

intent to distribute, in violation of 21 U.S.C. § 841. On appeal, Collier raises several

issues. On all issues, we affirm the judgment of the district court.1

1

The Honorable D.P. Marshall Jr., then Chief Judge, now United States 

District Judge for the Eastern District of Arkansas.
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I. Background

While patrolling Interstate 40 in Lonoke County, Arkansas, State Police 

Corporal Travis May saw a motorist drift into the shoulder. He initiated a traffic 

stop. May walked up to the car, greeted the motorist, and asked if he was “doing 

okay.” Gov’t Ex. 2, at 1:44. May noticed that the motorist’s “hands were shaking 

pretty uncontrollably” and that the car interior had a “lived-in look” with “lots of 

trash” and “signs of hard travel.” R. Doc. 125, at 34. The motorist, Collier, was a 

resident of Greenville, Mississippi, and he was driving a car rented in Las Vegas, 

Nevada, with a Utah license plate. May asked Collier about his travel plans. Collier 

said that he drove from Mississippi to Little Rock, Arkansas, to shop for tires. 

Collier’s shaking hands, disorderly car interior, and unusual itinerary aroused May’s 

suspicion. 

May believed further inquiry was warranted. He asked Collier if he had any 

weapons or drugs in the car. Collier replied that he did not. May took Collier’s

driver’s license back to the patrol vehicle. He ran a routine warrant check, which 

came back clear. When May returned to Collier’s car, he asked Collier for 

permission to conduct a search. Collier declined. May then told Collier to wait

because he was calling a K-9 unit to the traffic stop.

2

The K-9 unit, consisting of Arkansas State Police Sergeant Mark Blackerby 

and the drug-detection dog Raptor, arrived about four minutes later. Blackerby 

explained to Collier that he would run Raptor around the car, and if Raptor smelled

drugs, Blackerby and May would have probable cause to conduct a search.

Blackerby ran Raptor around the car. Raptor smelled drugs and alerted to their 

presence. However, Raptor was unable to pinpoint the drugs’ exact location. May 

2

On appeal, Collier does not make, and therefore waives, any argument that

May unreasonably prolonged the traffic stop. See United States v. Cooper, 990 F.3d 

576, 583 (8th Cir. 2021) (“Ordinarily, a party’s failure to make an argument in [his]

opening brief results in waiver of that argument.”). 
-3- 

and Blackerby proceeded with a search. They found a small amount of marijuana

intermingled with Collier’s personal belongings. More importantly, they recovered

ten bundles of white powder, which appeared to be cocaine. They arrested Collier.

Authorities later determined that the bundles contained about 10.08 kilograms 

of white powder. Powder from two bundles field-tested positive for cocaine. The 

bundles were sent to the Arkansas State Crime Laboratory for further analysis. The 

laboratory’s analysis confirmed that the powder was cocaine.

The federal government obtained a one-count indictment against Collier for 

unlawful possession of cocaine with intent to distribute, in violation of 21 U.S.C. 

§ 841(a)(1) and (b)(1)(A). Collier pleaded not guilty, and the case proceeded to trial. 

The jury found Collier guilty. The district court subsequently imposed a statutory 

minimum sentence of ten years’ imprisonment. Collier appeals. 

II. Discussion

On appeal, Collier raises six principal issues. We address these issues in the 

order that he presents them. On all six issues, we affirm.

A. Reliability of the Drug-Detection Dog

First, Collier challenges the reliability of the canine, Raptor, to satisfactorily

detect illicit drugs. He also contends that Raptor’s alert was insufficient to establish 

probable cause to search Collier’s car. See U.S. Const. amend. IV (recognizing “[t]he 

right of the people to be secure in their persons, houses, papers, and effects, against 

unreasonable searches and seizures . . . [without] probable cause”). 

“We review de novo the district court’s legal determination of probable 

cause.” United States v. Perez, 29 F.4th 975, 986 (8th Cir. 2022) (quoting United 

States v. Gonzalez, 781 F.3d 422, 429 (8th Cir. 2015)). A dog is presumptively

reliable at detecting illicit drugs—and its alert establishes probable cause for a 

search—if the dog has satisfactorily completed a bona fide certification or training 

program. Florida v. Harris, 568 U.S. 237, 246–47 (2013). “This presumption may 
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be overcome if a defendant can show” by cross-examination or opposing evidence 

“the inadequacy of [the] certification or training program or that the circumstances 

surrounding a canine alert undermined the case for probable cause.” Perez, 29 F.4th 

at 986 (quoting Gonzalez, 781 F.3d at 429).

We reject Collier’s challenge to Raptor’s reliability. Before encountering

Collier’s car, Raptor completed a 320-hour basic training course under the Arkansas 

State Police. Collier concedes that Raptor maintained its drug-detection skills 

through “coordinated monthly sessions.” Appellant’s Br. at 11. The record contains 

no opposing evidence undermining Raptor’s reliability. The record shows that 

authorities had previously deployed Raptor 158 times, it had alerted 73 times, and 

authorities had discovered illicit drugs 71 times. In the field, Raptor’s accuracy rate 

was 97 percent. Our cases hold that, absent contradictory circumstances, a trained 

dog’s alert will establish probable cause when the dog’s previous in-field accuracy 

rate exceeds 50 percent. See United States v. Holleman, 743 F.3d 1152, 1157 (8th 

Cir. 2014) (57 percent); United States v. Donnelly, 475 F.3d 946, 955 (8th Cir. 2007)

(54 percent). Raptor far surpassed our circuit’s 50-percent standard.3

Collier also questions how Raptor alerted,

4 suggesting that its alert was 

insufficiently “profound.” Appellant’s Br. at 2, 12. Our “probable cause inquiry is 

always fact specific.” United States v. Tuton, 893 F.3d 562, 571 (8th Cir. 2018). 

Every dog is unique, and a dog that smells illicit drugs is not required to 

communicate with its handler in any specific way. See Holleman, 743 F.3d at 1156. 

“Dogs alert in many different manners. One dog may alert in one manner while 

3

That is not to say that a dog with less than 50-percent accuracy is useless. 

The court evaluates a dog-sniff case, like any other probable-cause case, “under the 

totality of the circumstances.” Donnelly, 475 F.3d at 954. Thus, the alert of a lowaccuracy dog, together with other circumstances that indicate the presence of illicit 

drugs, can establish probable cause for a search. See id. at 954–55.

4

See R. Doc. 79, at 8, 11 (discussing how Raptor “completely change[d]

directions” and “d[id] a 180” when it “smelled something”).
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another dog may alert in another manner.” United States v. Howard, 448 F. Supp. 

2d 889, 898 (E.D. Tenn. 2006), aff’d, 621 F.3d 433 (6th Cir. 2010). The reliability

of a dog’s alert, not its manner, is what matters. See Holleman, 743 F.3d at 1156 

(“Fourth Amendment jurisprudence does not require drug dogs to abide by a specific 

and consistent code in signaling their sniffing of drugs to their handlers.” (quoting 

United States v. Clayton, 374 F. App’x 497, 502 (5th Cir. 2010) (unpublished per 

curiam))). Based on the record, we conclude that Raptor’s own unique manner of 

alert reliably signaled the probable presence of illicit drugs.

Because Raptor was reliable and its alert was sufficient, Blackerby and May

had probable cause to search Collier’s car. The district court correctly admitted the

narcotics evidence derived from the search. 

B. Admission of the Dog-Training Expert

Second, Collier argues that the district court erred when it permitted Major 

Roby Rhoads, the K-9 coordinator for the Arkansas State Police, to give expert 

testimony at a suppression hearing about the Arkansas State Police’s dog-training 

program. Specifically, Collier argues that Rhoads was unqualified because Rhoads

was unaware that police dog training originated in the German “State of NorthrineWestfalia” (North Rhine-Westphalia), he could not pronounce or translate the 

German word “Polizeispurhundprüfung,” and he was unfamiliar with the history of 

the International Congress of Police Service Dogs. Appellant’s Br. at 8–9.5

“We review the decision of the district court to admit expert testimony for an 

abuse of discretion, giving substantial deference to the district court.” United States 

5

Collier’s opening brief attacks Rhoads’s expertise for several pages, but it 

does not specifically state what the district court should have done. Here, we will

assume that Collier argues for Rhoads’s exclusion. We will further assume without 

deciding that Daubert applies to suppression hearings. See generally Daubert v. 

Merrell Dow Pharms., Inc., 509 U.S. 579 (1993) (interpreting Fed. R. Evid. 702). 

But see United States v. Ozuna, 561 F.3d 728, 737 (7th Cir. 2009) (“[T]he primary 

rationale behind Daubert is not applicable in a suppression hearing.”).
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v. Primm, 63 F.4th 1186, 1190 (8th Cir. 2023). An expert is qualified if he has 

“knowledge, skill, experience, training, or education” that will enable him to give 

helpful testimony. See Fed. R. Evid. 702 (listing specific requirements). An expert’s

expertise must be “relevant to the task at hand.” Daubert, 509 U.S. at 597. A court 

should not concern itself with a proposed expert’s knowledge, skill, experience, 

training, or education in extraneous and irrelevant matters. See Fed. R. Evid. 402 

(“Irrelevant evidence is not admissible.”).

Here, Collier’s challenge to Rhoads’s expert testimony lacks merit. Rhoads’s 

ignorance of certain obscure facts related to police dog training did not discredit his 

otherwise unobjected-to training and experience in the field. The geographic origin, 

etymology, and history of police dog training are not relevant to the manner and 

efficacy of the Arkansas State Police’s current program. The district court did not 

abuse its discretion by permitting Rhoads to give expert testimony. 

C. Standard for a Motion to Suppress

Third, Collier argues that the district court legally erred when it ruled on his 

motion to suppress because it “utilized the wrong standard for suppression.” 

Appellant’s Br. at 11 (cleaned up). Specifically, Collier argues that the court used a 

“reasonable officer” standard and that it should have used a “reasonably prudent 

person” standard or a “reasonable person” standard. Id. at 12–13. The question of 

the appropriate standard for a motion to suppress is a question of law that we review 

de novo. See United States v. Mallari, 334 F.3d 765, 766 (8th Cir. 2003). 

In the Fourth Amendment context, the terms “reasonable officer,” “reasonably 

prudent person,” and “reasonable person” are functionally equivalent. We have used 

these terms interchangeably. See, e.g., United States v. Vittetoe, 86 F.4th 1200, 1203 

(8th Cir. 2023); United States v. Lewis, 864 F.3d 937, 946–47 (8th Cir. 2017); United 

States v. Anderson, 674 F.3d 821, 826–27 (8th Cir. 2012). Other circuits have done

the same. See, e.g., Edmond v. United States, 899 F.3d 446, 453–54 (7th Cir. 2018); 

United States v. Martin, 613 F.3d 1295, 1301 (10th Cir. 2010) (Gorsuch, J.); United 

States v. Ibarra, 345 F.3d 711, 716 (9th Cir. 2003). And the Supreme Court has used 
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each of these terms—and many similar terms—with no indication that it intended to 

impose an unalterable formulation. See, e.g., Plumhoff v. Rickard, 572 U.S. 765, 777 

(2014) (“reasonable police officer”); Harris, 568 U.S. at 248 (“reasonably prudent 

person”); Maryland v. Pringle, 540 U.S. 366, 372 (2003) (“reasonable officer”); 

Florida v. Jimeno, 500 U.S. 248, 251 (1991) (“reasonable person”); Maryland v. 

Buie, 494 U.S. 325, 332 (1990) (“reasonably prudent officer”); Brinegar v. United 

States, 338 U.S. 160, 175 (1949) (“reasonable and prudent men”); Johnson v. United 

States, 333 U.S. 10, 14 (1948) (“reasonable men”); Carroll v. United States, 267 

U.S. 132, 162 (1925) (“a man of reasonable caution”); Stacey v. Emery, 97 U.S. 642, 

645 (1878) (“a man of prudence and caution”). 

Based on our review of the Fourth Amendment case law, we reject Collier’s 

argument that reversal is required here because the district court’s denial of his

motion to suppress did not use a specific phrase. The district court’s evaluation was 

clearly one of reasonableness. An evaluation for reasonableness, in light of the 

totality of the circumstances, is all the case law requires. See Brigham City v. Stuart, 

547 U.S. 398, 403 (2006) (calling “reasonableness” the Fourth Amendment’s 

“ultimate touchstone” (internal quotation marks omitted)); Illinois v. Gates, 462 U.S. 

213, 230–32 (1983) (holding that the Fourth Amendment analysis turns on common 

sense or practical judgment, not technicalities). 

D. Rule 16(a) Disclosures

Fourth, Collier argues that the government violated Federal Rule of Criminal 

Procedure 16(a)(1)(G) by providing inadequate expert disclosures about Senior 

Forensic Chemist Dan Hedges of the Arkansas State Crime Laboratory before 

Hedges testified at trial. Thus, Collier contends that the district court should have 

excluded Hedges or else limited the scope of his testimony.

“We review the decision of the district court to admit expert testimony for an 

abuse of discretion, giving substantial deference to the district court.” Primm, 63 

F.4th at 1190. “A defendant asserting reversible error under Rule 16(a)(1)(G) must 

demonstrate prejudice resulting from the district court’s decision to admit the 
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contested testimony.” United States v. Waln, 916 F.3d 1113, 1115 (8th Cir. 2019)

(quoting United States v. Kenyon, 481 F.3d 1054, 1062 (8th Cir. 2007)). Prejudice 

exists when the government’s failure to make adequate disclosures unfairly surprises 

the defendant, see Fed. R. Crim. P. 16 advisory committee’s note to 1993 

amendment, or deprives the defendant of “a fair opportunity to prepare to crossexamine [the] expert witness[] and secure opposing expert testimony if needed,” id.

advisory committee’s note to 2022 amendments; see McClendon v. United States, 

587 F.2d 384, 388–89 (8th Cir. 1978) (stating that prejudice exists when the 

government surprises the defendant and thereby prevents him from “conduct[ing] a 

thorough cross-examination of each of the government witnesses at the trial”). 

Here, the government provided Collier’s counsel with copies of Hedges’s 

curriculum vitae and laboratory analysis in December 2022, well in advance of 

Collier’s August 2023 trial. Collier’s counsel waited until trial to challenge these 

disclosures, arguing that “[w]e are unsure if they are complete.” R. Doc. 126, at 100.

The district court asked counsel whether he sought to exclude Hedges, and he replied

that he “believe[d]” so. Id. at 102. The court reminded counsel that it had given the 

parties a deadline, “21 days before trial,” for moving to exclude a witness. Id. at 107. 

Collier’s counsel could not provide a “sufficient response” for why he missed the 

court’s deadline. Id. at 108 (quoting the court). The court ruled that Collier would 

suffer “no prejudice . . . by allowing the expert to testify.” Id. at 120. The court

stated, “[M]y scheduling order means what it says.” Id.

Assuming without deciding that the government’s expert disclosures about 

Hedges were inadequate (an issue the parties dispute in their briefs), Collier suffered 

no prejudice for three reasons. First, the government made its disclosures more than 

seven months before trial—“a point in time early enough to avoid any possibility of 

prejudice resulting from surprise.” McClendon, 587 F.2d at 388. Collier’s defense 

had ample time to seek additional disclosures if it thought they were necessary. 

Second, given how far in advance the government made its disclosures, Collier’s 

defense had “a fair opportunity to prepare to cross-examine [Hedges] and secure 

opposing expert testimony if needed.” Fed. R. Crim. P. 16 advisory committee’s 
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note to 2022 amendments. Third, Collier’s motion to exclude Hedges’s testimony 

was untimely, and a district court is justified in enforcing its reasonable deadlines. 

See Fed. R. Crim. P. 12(c)(3) (“If a [defendant] does not meet the [district court’s] 

deadline for making a [Rule 16 discovery] motion, the motion is untimely.”); United 

States v. Trobee, 551 F.3d 835, 838 (8th Cir. 2009) (“Courts have a legitimate 

interest in the enforcement of scheduling deadlines, both to manage a pending case 

and to retain the credibility of these deadlines in future cases.”). 

In other words, when the government makes its expert disclosures early and 

the defendant brings his motion late, the district court does not abuse its discretion 

by denying the defendant’s untimely motion. See Fed. R. Crim. P. 12(c)(3). Even if 

the government’s Rule 16(a)(1)(G) disclosures are inadequate, a defendant suffers 

no prejudice when his failure to request additional disclosures or prepare for crossexamination is the result of his own neglect. Like the district court, we discern no 

prejudice against Collier. When the court denied Collier’s untimely motion and 

admitted Hedges as an expert witness, it acted within its discretion.

In addition, Collier contends that the government should have made expert 

disclosures for Sergeant Blackerby, who testified about Raptor’s alert at the traffic 

stop. The court ruled that Blackerby could testify as a lay witness, with no expert 

disclosures, because his testimony was not “in the realm of real expert testimony.” 

R. Doc. 126, at 45–48. Collier appeals the court’s ruling but provides no case law to 

support his argument. See Appellant’s Br. at 16–17. The government replies that the 

handler of a drug-detection dog may testify as a lay witness and that, consequently, 

expert disclosures are not required. See Appellee’s Br. at 27–28.

Whether the officer who handles a drug-detection dog is an expert witness, 

for whom expert disclosures are required, or a lay witness, for whom expert

disclosures are not required, appears to be an issue of first impression in our court. 

The Supreme Court has not spoken clearly on this issue. See Harris, 568 U.S. at 247

(“A defendant . . . must have an opportunity to challenge such evidence of a dog’s 

reliability, whether by cross-examining the testifying officer or by introducing his 
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own fact or expert witnesses.” (emphases added)). And among our sister circuits, 

only the First Circuit seems to have addressed the issue. See United States v. 

Naranjo-Rosario, 871 F.3d 86, 96–97 (1st Cir. 2017) (holding that officers who 

handle drug-detection dogs are expert witnesses). 

We need not answer the question here. Regardless of Blackerby’s expert or 

lay status, Collier has not “demonstrate[d] prejudice” due to the absence of expert 

disclosures. Waln, 916 F.3d at 1115 (quoting Kenyon, 481 F.3d at 1062); cf. United 

States v. Mackey, 83 F.4th 672, 677 (8th Cir. 2023) (rejecting a defendant’s 

“conclusory argument” about an expert witness’s professional experience). Collier

has not shown that he was surprised when the government called Blackerby to 

testify. See McClendon, 587 F.2d at 388; R. Doc. 69 (identifying Blackerby as a 

government witness in June 2023). He also has not shown that he lacked “a fair 

opportunity to prepare to cross-examine [Blackerby] and secure opposing expert 

testimony if needed.” Fed. R. Crim. P. 16 advisory committee’s note to 2022 

amendments. Thus, we affirm the district court’s admission of Blackerby’s

testimony without expert disclosures. 

E. Cocaine Isomer Defense

Fifth, Collier raises a non-meritorious technical defense known as the 

“cocaine isomer defense.” See United States v. Francesco, 725 F.2d 817, 820 n.1

(1st Cir. 1984) (collecting cases from eight circuits). This defense maintains “that 

the chemical identification tests used by the government [cannot] adequately 

distinguish between allegedly legal and concededly illegal forms of cocaine” and, 

therefore, that prosecutions for cocaine possession “must fail for want of proof.” 

United States v. Ortiz, 610 F.2d 280, 281 (5th Cir. 1980) (per curiam).

Specifically, Collier concedes that federal law bans “cocaine, its salts, optical 

and geometric isomers, and salts of isomers,” 21 U.S.C. § 841(b)(1)(A)(ii)(II) 

(emphasis added), but he argues that his ten bundles of white powder could have 

contained a non-illicit, positional isomer of cocaine. At the district court, Collier

asserted that the government’s tests could not adequately distinguish between illegal 
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cocaine and his purportedly legal positional isomer of cocaine. Collier requested a 

special jury instruction on this defense, and he moved for a judgment of acquittal. 

The court declined to give such an instruction, and it entered judgment on the jury’s 

guilty verdict. These decisions were not erroneous. 

Neither party identifies, nor have we located, a case from our circuit that is 

directly on point. See United States v. Luschen, 614 F.2d 1164, 1168–70 (8th Cir.

1980) (rejecting a different version of the cocaine isomer defense that involved

different issues); see also United States v. Myers, 56 F.4th 595, 597–99 (8th Cir. 

2022) (applying the categorical approach and comparing Missouri’s definition of 

cocaine with the federal definition); United States v. Owen, 51 F.4th 292, 294–96

(8th Cir. 2022) (per curiam) (same with Minnesota’s definition); United States v. 

Oliver, 987 F.3d 794, 807 (8th Cir. 2021) (same with Illinois’s definition). Rather, 

we look to the First Circuit’s decision in United States v. Francesco, 725 F.2d 817. 

We agree with the parties that Francesco is directly on point and persuasive. See 

Appellant’s Br. at 18–19 (citing Francesco twice); Appellee’s Br. at 2, 30–31 (citing 

Francesco as an apposite authority and again in the body of the brief).

In Francesco, federal agents seized a package “contain[ing] approximately 

one kilogram of a white powdery substance identified as cocaine.” 725 F.2d at 819. 

At his trial for possession with intent to distribute, the defendant argued that the 

substance was not illegal cocaine but a legal cocaine isomer. Id. at 819–20. Based 

on this argument, he requested a special jury instruction and moved for a judgment 

of acquittal. Id. The district court ruled against the defendant on both points, the jury 

returned a guilty verdict, and the court entered judgment accordingly. Id. 

On appeal, the First Circuit affirmed. Id. at 820. It explained that there are 

multiple isomers of cocaine, including (1) “narcotic” isomers,6 which are unlawful 

to possess, and (2) non-narcotic isomers, which are chemically related but are not 

6

In legal usage, the word “narcotic” may refer to any “drug that is controlled 

or prohibited by law.” Narcotic, Black’s Law Dictionary (12th ed. 2024).
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themselves unlawful. Id. at 820–21. Despite this distinction, the First Circuit upheld

the conviction. Id. at 820. At trial, “government experts testified that the substances 

seized from [the defendant] were ‘cocaine,’” and the defendant offered no evidence 

to the contrary. Id. at 821. Accordingly, the First Circuit held: 

The defendant’s failure to introduce evidence in support of his isomer 

defense left the judge (whose instructions to the jury must be based on 

the evidence adduced at trial) no choice but to instruct the jury that 

cocaine is a Schedule II controlled substance. The jury then had no 

alternative but to find that the substances identified as cocaine were 

illegal forms of cocaine under the Drug Control Act. The instruction to 

the jury was not erroneous and the jury was justified in finding the 

defendant guilty of possession of a Schedule II controlled substance.

Id. at 821–22. 

We adopt the First Circuit’s approach here. When the government produces

evidence that a defendant possessed illegal cocaine, the defendant is not entitled to 

a special jury instruction on his cocaine isomer defense, unless he produces or points 

to evidence that supports his position. See id. This rule accords with our circuit 

precedent. See United States v. Morales, 684 F.3d 749, 756 (8th Cir. 2012) (“A 

defendant is entitled to a particular jury instruction when the instruction [1] provides 

a correct statement of the law and [2] is supported by the evidence.” (quoting United 

States v. Harper, 466 F.3d 634, 649 (8th Cir. 2006))). And this rule does not relieve 

the government of its burden to “prove every element of a crime beyond a reasonable 

doubt.” Jones v. Hendrix, 599 U.S. 465, 487 (2023). The identity of a controlled 

substance is always an element of the offense. See 8th Cir. Model Jury Instructions: 

Criminal § 6.21.841A (2023) (requiring the government to prove that “the defendant 

was in possession of (describe substance, e.g., cocaine)”). 

Beyond a reasonable doubt, Collier’s jury expressly found that he possessed

“cocaine.” R. Doc. 95. Because his cocaine isomer defense was speculative and not 
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supported by evidence, we hold that the district court did not abuse its discretion by

denying a special jury instruction. See United States v. Wright, 993 F.3d 1054, 1064 

(8th Cir. 2021) (“We review jury instructions for an abuse of discretion.”).7

For similar reasons, we hold that the district court did not err when it denied

Collier’s motion for a judgment of acquittal. See United States v. Sainz Navarrete, 

955 F.3d 713, 718 (8th Cir. 2020) (“We review the denial of a motion for judgment 

of acquittal de novo.”). A judgment of acquittal, negating the jury’s guilty verdict, 

“is warranted only when no reasonable jury could [have found] all the elements 

beyond a reasonable doubt.” Wright, 993 F.3d at 1065 (quoting United States v. 

Parsons, 946 F.3d 1011, 1014 (8th Cir. 2020)). Based on the evidence presented at 

trial, a reasonable jury could have concluded that Collier’s bundles of white powder 

were illegal cocaine rather than a non-narcotic cocaine isomer. See United States v. 

Hall, 552 F.2d 273, 276 (9th Cir. 1977) (rejecting a cocaine isomer defense). 

F. Curative Instruction

Sixth, during its closing argument, the government briefly commented on 

Collier’s post-arrest, post-Miranda silence. See Miranda v. Arizona, 384 U.S. 436

(1966); R. Doc. 127, at 91 (“Mr. Collier said nothing.”). Collier moved for a mistrial, 

and the district court denied his motion. The court offered to give a curative 

instruction instead. Collier’s counsel replied, “We’ll leave it with the [c]ourt to do 

what the [c]ourt thinks appropriate.” R. Doc. 127, at 98. The court advised the parties 

of the instruction it would give, and Collier’s counsel replied, “Thank you, Your 

7

Defendants may present evidence-free defenses. See United States v. Willis, 

101 F.4th 577, 585 (8th Cir. 2024) (acknowledging that defendants have a right to 

put forward “unorthodox defenses”); Gill v. Maciejewski, 546 F.3d 557, 564 (8th 

Cir. 2008) (noting that “a criminal defendant has no burden to present evidence or 

call witnesses” (emphasis omitted)). However, asserting an evidence-free defense 

does not entitle the defendant to a special jury instruction. Morales, 684 F.3d at 756. 

Instead, the defendant must try to raise reasonable doubt in the jurors’ minds within 

the limits of the ordinary instructions. Here, Collier’s jury was free to entertain the 

view that Collier possessed ten bundles of a non-narcotic cocaine isomer. 
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Honor.” Id. at 98–99. Collier now challenges the denial of a mistrial and argues that 

the jury instruction was insufficient to cure the Miranda violation.

Assuming without deciding that a Miranda violation occurred, we review for 

abuse of discretion the district court’s denial of a motion for a mistrial. United States 

v. Shield, 87 F.4th 883, 885 (8th Cir. 2023). “The prejudicial effect of any improper 

[comment] is determined by examining the context of the error and the strength of 

the evidence of the defendant’s guilt.” Id. (quoting United States v. Hollins, 432 F.3d 

809, 812 (8th Cir. 2005)). Curative instructions are ordinarily preferable to mistrials 

and “generally sufficient to alleviate prejudice.” United States v. Diaz-Pellegaud, 

666 F.3d 492, 503 (8th Cir. 2012) (quoting United States v. Davidson, 122 F.3d 531, 

538 (8th Cir. 1997)). 

Upon our review of the trial transcript, we conclude that the government’s 

comment on Collier’s post-Miranda silence was fleeting. See R. Doc. 127, at 91 

(“Mr. Collier said nothing.”). The district court indicated that the jury might not have

noticed the comment and would not place weight on it. See id. at 98 (“I don’t want 

to call undue attention to this and leaving it alone might well be the better practice.”). 

Given the comment’s fleeting nature, the minor role that it played in the context of 

the government’s much broader closing argument, and the weight of the evidence 

against Collier, we hold that the district court did not abuse its discretion by giving 

a curative instruction rather than granting a mistrial. Cf. United States v. Askew, 98 

F.4th 116, 126 (4th Cir. 2024) (holding that a “fleeting reference” to a defendant’s 

exercise of Miranda rights does not “constitute[] a per se due process violation”); 

United States v. Reeves, 742 F.3d 487, 505 (11th Cir. 2014) (“[A] single, 

inappropriate reference to a defendant’s post-arrest silence that is not mentioned 

again is too brief to constitute a Fifth Amendment violation.”). 

Turning to the curative instruction’s content, we note that Collier’s counsel

thanked the district court and did not object, so we review for plain error. See United 

States v. Refert, 519 F.3d 752, 756 (8th Cir. 2008). “Plain error only exists if (1) 

there was an error, (2) the error was plain, (3) the error affected [Collier’s] 
-15- 

substantial rights, and (4) a failure to grant relief would seriously affect the fairness, 

integrity, or public reputation of judicial proceedings.” Id. (quoting United States v. 

Falcon, 477 F.3d 573, 577 (8th Cir. 2007)). Collier “fail[s] to show any error [in the 

instruction], let alone error that was plain.” United States v. Rodriguez, 984 F.3d 

704, 711 (8th Cir. 2021). Therefore, we affirm the instruction. See id. at 711 n.4.

III. Conclusion

To the extent that Collier suggests other issues with the Arkansas State Police

and the proceedings in the district court,8 we consider the issues inadequately briefed 

and his arguments waived. The judgment of the district court is affirmed.

______________________________

8

See, e.g., Appellant’s Br. at i (referring to “numerous contested issues” at the 

district court); id. at 9 (claiming that the Arkansas State Police’s dog-training 

program is “defunct”); id. at 10 (claiming that “a chasm of errors and discrepancies 

exist[s]” in the Arkansas State Police’s official records).