United States Court of Appeals

FOR THE DISTRICT OF COLUMBIA CIRCUIT

Argued November 2, 2011 Decided December 9, 2011

No. 10-3043

UNITED STATES OF AMERICA,

APPELLEE

v.

LEONEL RENE GUERRERO,

APPELLANT

Appeal from the United States District Court

for the District of Columbia

(No. 1:08-cr-00347-1)

Robert A. Sheffield, appointed by the court, argued the cause

for appellant. With him on the briefs was Douglas J. Behr. A.

J. Kramer, Federal Public Defender, entered an appearance. 

Stratton C. Strand, Assistant U.S. Attorney, argued the

cause for appellee. With him on the brief was Ronald C.

Machen Jr., U.S. Attorney, and Roy W. McLeese III and

Elizabeth Trosman, Assistant U.S. Attorneys.

Before: ROGERS and KAVANAUGH, Circuit Judges, and

WILLIAMS, Senior Circuit Judge.

Opinion for the Court by Circuit Judge ROGERS.
2

ROGERS, Circuit Judge: Claiming trial evidentiary errors,

appellant Leonel Rene Guerrero seeks reversal of his conviction

by a jury for unlawful possession with intent to distribute cocaine

and aiding and abetting. His principal contention is that the

district court plainly erred in allowing a law enforcement officer

to offer lay opinion testimony pursuant to Federal Rule of

Evidence 701 about the drug-trafficking significance of items

seized from his bedroom and that to the extent the officer’s

opinion testimony was admissible he first had to be qualified as

an expert pursuant to Federal Rule of Evidence 702. Because

appellant elicited testimony concerning the officer’s law

enforcement experience with drug trafficking in an attempt to

demonstrate he was conditioned to see the benign items seized

from appellant’s bedroom as drug paraphernalia, and elicited his

opinion regarding one of those items, appellant fails to show

prejudice even assuming the testimony was improperly admitted. 

Circuit precedent confirms his other contentions are without

merit. The district court neither abused its discretion in

excluding expert evidence on the ultimate question in the case,

nor erred in allowing the prosecutor to ask guilt-assuming

hypothetical questions of a character witness testifying about her

personal opinion. Accordingly, we affirm the judgment of

conviction.

I.

On October 17, 2008, appellant accepted delivery at his

house of a package that was shipped from El Salvador and

addressed to Carlos Lopez. Inside the package was a gold statue

containing 302.6 grams of cocaine. Law enforcement officials

had intercepted the package upon its arrival in the United States

and installed a trip wire to signal when the package was opened. 

When the wire was tripped thirty minutes after appellant

accepted the package, law enforcement officers, including

Special Agents from Immigration and Customs Enforcement,
3

were admitted into the house, upon identifying themselves, by

two women. In the basement, the agents found appellant poised

to exit into the backyard and Jose Luis Sacreas as well as a third

man and the opened package. The agents searched the house. 

Special Agent Drewniak seized a number of items from

appellant’s bedroom on the second floor: two coffee grinders, a

digital scale, a small white ceramic bowl, a small white spoon,

a jar of creatine, cotton gloves, small plastic baggies, and $707

in cash; the coffee grinders and the scale contained white residue

later identified as a mixture of cocaine and lidocaine. Appellant

and Sacreas were indicted for unlawful possession with intent to

distribute cocaine, 21 U.S.C. §§ 841(a)(1), 841(b)(1)(C), and

aiding and abetting, 18 U.S.C. § 2.

Agent Drewniak, along with three other Special Agents who

participated in the controlled delivery of the package, testified at

trial. Drewniak testified on direct examination that the items

seized from appellant’s bedroom were “consistent with narcotics

distribution activity.” Tr. 5/19/09 at 116. He explained that

“typically” coffee grinders are used to mix cutting agents such as

creatine with pure cocaine, small bowls are used to hold small

amounts of cocaine, small spoons are used to scoop and move

small quantities of cocaine, scales are used to measure small

quantities of cocaine, gloves are used to keep cocaine from being

absorbed into the skin, and small baggies are used to package

cocaine for sale. Tr. 5/19/09 at 116, 119, 120–23, 125; Tr.

5/20/09 at 6. On cross examination, appellant, through counsel,

questioned Drewniak about the extent of his law enforcement

experience and training, prompting him to testify that he had

been trained to conduct surveillance, search a crime scene,

interview witnesses, conduct a through investigation and had

“conducted numerous controlled deliveries” of unlawful drugs. 

Tr. 5/20/09 at 15. Counsel also inquired, “What is the

significance of this little plate, the drug significance?” and

Drewniak testified that “in the drug distribution enterprises
4

typically small bowls and small plates are utilized in a fashion to

mix pure cocaine that is imported into the country with diluting

agents such as benzocaine or creatine.” Tr. 5/20/09 at 25. 

Other government witnesses included forensic chemists

from the Drug Enforcement Administration. These chemists

testified that they had found cocaine on the grinders and scale

and that creatine is a cutting agent often mixed with pure cocaine

to add bulk and dilute the cocaine. Two of appellant’s superiors

at the Washington Hilton Hotel testified that appellant’s job as

a steward involved pushing large carts of soiled dishware that he

washed in a dishwasher, that he had no problem doing any facet

of his job, and that he was among the hotel’s best stewards and

would supervise anywhere between two to fifteen employees on

weekends. 

In defense, appellant presented the testimony of his wife and

an expert witness as well as a coworker and a neighbor. His wife

testified they had bought the house in 2001, and she had lived

there until June 2008 when she and their children moved to

Maryland. Sometime after June 2008, appellant began renting

out rooms in the house and there were nine tenants at the time

appellant was arrested. She recognized the items seized from

appellant’s bedroom, explaining that she had used the creatine to

build muscle so she might more easily lift beds in her work as a

housekeeper, the scale to weigh gold jewelry that she purchased

in Peru and sold during the holidays, the coffee grinders to grind

coffee, and the spoon to feed her small children. Appellant wore

the cotton gloves at work to hold hot plates and used the baggies

to carry his medicine to work. On cross-examination she

acknowledged that the seized baggies were smaller than those

she bought for carrying appellant’s medicine and that she did not

know how the coffee grinders and scale came to have cocaine

residue on them. 
5

Dr. Stephen J. Feinberg, an optometrist specializing in low

vision, testified that he had examined appellant and reviewed his

medical records and concluded that there is “no normal . . .

architecture, in the retina of [appellant’s] eyes,” his “peripheral

vision is not very good; his central vision . . . is nonexistent,” and

his vision is twelve times worse than that needed to qualify as

legally blind even with corrective lenses. Tr. 5/21/09 at 50, 54. 

Although appellant could identify the denomination of paper

currency by holding it within five inches of his eyes, he would

have difficulty distinguishing white powder on a white surface. 

Appellant’s co-worker testified that he realized from the first

day that he met appellant over a decade ago that “he could not

see properly,” Tr. 5/20/09 at 163, and that he knew appellant to

be a law-abiding person. His next-door neighbor testified that

she was aware appellant had trouble with his eyesight, she would

drive him to and from work three or four times a week, and knew

him to be a law-abiding person. When asked on cross

examination whether her opinion would change if told that

appellant had been charged with unlawful possession with intent

to distribute cocaine and had the items necessary to prepare and

package cocaine for sale in his bedroom, she testified her opinion

would not change because she did not believe that appellant was

guilty.

The jury found appellant guilty and the district court

sentenced him to time served and 36 months supervised release. 

Appellant appeals.

II. 

Federal Rule of Evidence 701, “Opinion Testimony by Lay

Witnesses,” provides:

If the witness is not testifying as an expert the witness’
6

testimony in the form of opinions or inferences is

limited to those opinions or inference which are (a)

rationally based on the perception of the witness, (b)

helpful to a clear understanding of the witness’

testimony or the determination of a fact in issue, and (c)

not based on scientific, technical, or other specialized

knowledge within the scope of [Federal] Rule [of

Evidence] 702.1

These rules are designed to draw a distinction between lay and

expert testimony and to ensure that any testimony “based on

scientific, technical, or other specialized knowledge” is

“scrutinized under the rules regulating expert opinion.” FED.R.

EVID. 701, 2000 amendment advisory committee note. Proper

lay opinion testimony is not based on specialized knowledge and

is “the product of reasoning processes familiar to the average

person in everyday life.” United States v. Wilson, 605 F.3d 985,

1025 (D.C. Cir. 2010) (quoting United States v. Garcia, 413 F.3d

201, 215 (2d Cir. 2005)).

Appellant contends that Special Agent Drewniak’s lay

opinion testimony about the drug-trafficking significance of the

items seized from his bedroom was improper lay opinion

1

 Federal Rule of Evidence 702, “Testimony by Experts,”

provides: 

If scientific, technical, or other specialized knowledge will

assist the trier of fact to understand the evidence or to

determine a fact in issue, a witness qualified as an expert by

knowledge, skill, experience, training, or education, may

testify thereto in the form of an opinion or otherwise, if (1)

the testimony is based upon sufficient facts or data, (2) the

testimony is the product of reliable principles and methods,

and (3) the witness has applied the principles and methods

reliably to the facts of the case.
7

testimony under FED. R. EVID.701 for three reasons: (1) his

opinions were not limited to those rationally based on his

firsthand experience of searching appellant’s bedroom; (2) his

opinion testimony merely told the jury that he believed appellant

was selling cocaine and, therefore, was not helpful to the jury;

and (3) to the extent there was a basis for admission of his

opinion testimony, it was due to knowledge of the modus

operandi of cocaine dealers, specialized knowledge which falls

within the scope of FED.R.EVID.702. Because appellant did not

object at trial to the admission of Drewniak’s opinion testimony,

our review is for plain error, see United States v. Weaver, 281

F.3d 228, 231 (D.C. Cir. 2002), and appellant must show there

is error that is clear or obvious, and the error affected his

substantial rights, which in the ordinary case means it affected

the outcome of the trial, and the error seriously affects the

fairness, integrity, or public reputation of judicial proceedings,

see United States v. Marcus, 130 S. Ct. 2159, 2164 (2010);

United States v. Olano, 507 U.S. 725, 731 (1993). 

At the time of appellant’s trial, this court had held that “[t]he

operations of narcotics dealers” are “a suitable topic for expert

testimony because they are not within the common knowledge of

the average juror.” United States v. Boney, 977 F.2d 624, 628

(D.C. Cir. 1992); see also United States v. Dunn, 846 F.2d 761,

763 (D.C. Cir. 1988). Since appellant’s trial, the court has

clarified that a witness may testify as to the typical

characteristics of drug trafficking operations only if first

qualified as an expert pursuant to FED.R.EVID.702. See Wilson,

605 F.3d at 1026; United States v. Smith, 640 F.3d 358, 365

(D.C. Cir. 2011). The government maintains that because FED.

R. EVID.702 imposes “no . . . procedural requirements,” FED. R.

EVID. 702, 2000 amendment advisory committee note, and a

district court has “considerable leeway in deciding in a particular

case how to go about determining whether particular expert

testimony is reliable,” Kumho Tire Co. v. Carmichael, 526 U.S.
8

137, 152 (1999), it was permissible for the district court to allow

Drewniak to offer expert opinion testimony after listening to his

testimony describing his law enforcement experience. Perhaps,

but it is unnecessary to decide this question because, assuming

error, it did not affect the outcome of appellant’s trial. 

Appellant’s defense was that he did not have the visual

capacity to participate in a drug trafficking operation by cutting,

weighing, and packaging cocaine for sale. Defense counsel

theorized in opening and closing argument to the jury that

Sacreas, the basement tenant, had used the scale and coffee

grinders to prepare cocaine for distribution, without appellant’s

knowledge, and stored the items in appellant’s unlocked

bedroom. Part and parcel of this defense was that the Special

Agents who executed the controlled delivery were biased, having

been conditioned as a result of their law enforcement experience

and training to view the seized items, which have many possible

benign uses, as drug paraphernalia. Appellant now urges that

without Drewniak’s inadmissible lay opinion testimony linking

the items from appellant’s bedroom to cocaine distribution there

is a reasonable probability that the government would not have

met its burden of proof as to his intent to distribute cocaine. Yet

defense counsel conceded that all four Special Agents were

experienced law enforcement officers in drug trafficking and

treated Drewniak as an expert in drug trafficking operations. 

Tellingly, appellant offers no response in his Reply Brief. 

Consequently, assuming Drewniak’s lay opinion testimony

was improperly admitted pursuant to FED. R. EVID. 701,

appellant fails to show that the error affected his substantial

rights by affecting the outcome of his trial, see United States v.

Ramsey, 165 F.3d 980, 984 (D.C. Cir. 1999), or adversely

affected the fairness, integrity, or public reputation of the judicial

proceedings. 
9

III.

Rule 704 of the Federal Rules of Evidence, “Opinion on

Ultimate Issue,” provides that “[n]o expert witness testifying

with respect to the mental state or condition of a defendant in a

criminal case may state an opinion or inference as to whether the

defendant did or did not have the mental state or condition

constituting an element of the crime charged or of a defense

thereto.” Appellant contends that the district court abused its

discretion in excluding the expert evidence of an optometrist

specializing in low vision that appellant lacked the visual ability

to perform the activities underlying the charges. He maintains

this evidence was relevant, had an adequate basis in fact, and

addressed the issue of his capacity to use the seized items in his

bedroom to prepare and package cocaine for sale, an issue “quite

apart” from whether he possessed a particular mental state. 

Appellant’s Br. 36. 

Prior to Dr. Feinberg’s testimony, the district court ruled that

Dr. Feinberg’s written report, which included the statement “I do

not believe Mr. Guerrero has the visual ability to perform the

activities for which he’s been charged,” would not be admitted. 

Tr. 5/21/09 at 42 (quoting Dr. Stephen J. Feinberg’s Expert

Report). The district court ruled, rather, that Dr. Feinberg could

testify about what appellant “can see, what he could see in

October 2008, what he could do.” Id. at 41. Consistent with

these rulings, the district court allowed Dr. Feinberg to answer

the only two questions defense counsel asked relating to

appellant’s ability to use the items seized from his bedroom to

prepare and package cocaine for sale:

[DEFENSE COUNSEL]: Would it be easy for Mr. 

Guerrero to see a white powder on a silver table top?

[PROSECUTOR]: Objection, Your Honor.

[DEFENSE COUNSEL]: Based on your examination of
10

him and your knowledge of his visual acuity?

[DR. FEINBERG]: I would think it highly unlikely that

he would discern powder on a silver or white surface.

[DEFENSE COUNSEL]: Based on your examination of

him, would it be easier for him to see something blue

on a white surface than a clear plastic bag?

[PROSECUTOR]: Objection, Judge.

[THE COURT]: I’ll allow it.

 [DR. FEINBERG]: Well, the answer would be yes,

because I tend to harp on contrast. If I have family

members present, somebody with these kinds of issues,

I talk about contrast if they’re going to function with

some sense of normalcy. 

Id. at 59–60. 

In United States v. Salamanca, 990 F.2d 629 (D.C. Cir.

1993), the issue was whether the district court had erred in ruling

that a psychologist could not testify whether the defendant had

the capacity to have the mental state necessary for guilt. The

charges against Salamanca included attempting to kill a law

enforcement officer. At trial, the psychologist was permitted to

testify that in his opinion Salamanca suffered from “diffused

brain damage” consistent with alcohol abuse and that if a person

with this condition drank as much alcohol as Salamanca did on

the evening of the assault that person would have a diminished

capacity to think and plan. Id. at 636. This court rejected the

argument that the psychologist also should have been allowed to

testify as to “whether [Salamanca] had the ability and capacity

to plan an attack . . . under the circumstances,” id., holding that

the district court had “correctly restricted the scope of the expert

testimony, disallowing questions as to ‘the ultimate fact,’ and

providing leeway for [Salamanca] to elicit the witness’s opinion

about the capacities of a person of his purported mental condition

who had consumed the quantity of beer [Salamanca] allegedly
11

drank on the night of the assault,” id. at 637. 

Likewise here, the district court properly excluded Dr.

Feinberg’s opinion on the ultimate question of appellant’s guilt

or innocence, see FED. R. EVID. 704, and afforded defense

counsel leeway to establish appellant’s inability to see and

perform activities underlying the charged offenses. Appellant’s

insistence that he was prejudiced because the excluded evidence

would have responded directly to Agent Drewniak’s lay opinion

testimony and informed the jury about what appellant could see

ignores Dr. Feinberg’s considerable testimony about appellant’s

poor vision, including that his vision was twelve times worse

than someone who was legally blind. Indeed, defense counsel

relied on his testimony in arguing to the jury in closing that

appellant could “absolutely not” see well enough to prepare and

package cocaine for sale. Tr. 5/21/09 at 102. Because the

defense was allowed to present expert testimony that addressed

appellant’s visual limitations, the district court’s rulings were not

an abuse of discretion. See United States v. Smart, 98 F.3d 1379,

1386 (D.C. Cir. 1996).

IV.

Federal Rule of Evidence 405 permits cross examination of

a character witness only as to “relevant specific instances of

conduct.” Appellant contends guilt-assuming hypothetical

questions, by their nature, do not concern specific instances of

conduct and the district court plainly abused its discretion in

permitting the prosecutor to ask guilt-assuming hypothetical

questions of appellant’s neighbor. The prosecutor asked the

neighbor whether her opinion of appellant would change

“knowing the . . . charge is possession with intent to distribute

cocaine,” that items seized from appellant’s bedroom (two 

coffee grinders with cocaine residue, a digital scale, and plastic

baggies) were used for distributing cocaine, and that he had
12

“received . . . a gold statue laden with over 300 grams of

cocaine” on the day he was arrested. Tr. 5/20/09 at 183-84. To

the extent the presence of the items and appellant’s receipt of the

statue were undisputed, it may be that these questions were not

guilt assuming. Compare United States v. Guzman, 167 F.3d

1350, 1352 (11th Cir. 1999); United States v. Williams, 738 F.2d

172, 177 (7th Cir. 1984); United States v. Mason, 993 F.2d 406,

408 (4th Cir. 1993), with United States v. Smith-Bowman, 76

F.3d 634, 636 (5th Cir. 1996); United States v. Velasquez, 980

F.2d 1275, 1277 (9th Cir. 1992). We need not decide because

even if the questions were guilt-assuming, appellant cannot

show error, much less plain error. 

In United States v. White, 887 F.2d 267 (D.C. Cir. 1989), the

court held that “[c]ross-examination of witnesses who testify

only to the defendant’s community reputation with hypotheticals

assuming guilt may be improper,” but that “similar crossexamination of witnesses who -- as the witness did here -- give

their own opinion of the defendant’s character is not error.” Id.

at 274–75 (citations omitted); see United States v. Kellogg, 510

F.3d 188, 193-97 (3d Cir. 2007). Appellant’s neighbor testified

about her personal opinion of appellant’s character, not his

reputation in the community. Appellant acknowledges White,

but maintains it was wrongly decided, an argument that can only

be entertained by the en banc court. See LaShawn A. v. Barry,

87 F.3d 1389, 1395 (D.C. Cir. 1996).

Accordingly, because appellant fails to show plain error or

an abuse of discretion by the district court, we affirm the

judgment of conviction.