F I L E D

United States Court of Appeals

Tenth Circuit

March 24, 2006

Elisabeth A. Shumaker

Clerk of Court

PUBLISH

UNITED STATES COURT OF APPEALS

TENTH CIRCUIT

UNITED STATES OF AMERICA,

Plaintiff-Appellee,

v. No. 05-2117

MARTHA CECILIA MARES,

Defendant-Appellant.

APPEAL FROM THE UNITED STATES DISTRICT COURT

FOR THE DISTRICT OF NEW MEXICO

(D.C. NO. CR-04-310-JP)

Marc H. Robert, Assistant Federal Public Defender, Las Cruces, New Mexico, for

Appellant.

Laura Fashing, Assistant United States Attorney, Albuquerque, New Mexico, for

Appellee.

Before LUCERO, McWILLIAMS, and TYMKOVICH, Circuit Judges.

TYMKOVICH, Circuit Judge.

Defendant-Appellant Martha Mares was arrested at a border checkpoint on

December 14, 2002, while driving a car carrying 32.5 kilograms of marijuana

concealed in the gas tank. Prior to trial for this offense, on December 11, 2003,
-2-

Mares was again arrested at a border checkpoint carrying marijuana concealed in

her car’s gas tank. The district court admitted the evidence of the subsequent

arrest at trial under Fed. R. Evid. 404(b). 

Mares now appeals her jury conviction of possession with intent to

distribute marijuana in violation of 21 U.S.C. §§ 841(a)(1) and (b)(1)(D) and the

51-month sentence imposed by the district court. Mares argues that the district

court erred (1) in admitting evidence of a subsequent arrest for drug trafficking

that occurred nearly a year after the crime for which she was charged, and (2) in

imposing an excessive sentence. Because the district court did not abuse its

discretion in admitting evidence of a subsequent crime under Fed. R. Evid.

404(b), and since Mares’s 51-month sentence was reasonable, we AFFIRM the

district court.

I. Background

The Two Arrests. On December 14, 2002, Mares was arrested at a border

checkpoint just south of Alamogordo, New Mexico as she attempted to enter the

United States. Mares told U.S. Border Patrol agents the car belonged to a Mr.

Alejandro Dominguez who was “kind of” her boyfriend and had loaned Mares the

car so she, her friend, and her children could join him for a weekend of skiing in

Ruidoso, New Mexico. (R. Vol. IV at 49, 77–78.) The car had temporary licence

plates, and Mares produced a recent bill of sale for the vehicle. Border Patrol
-3-

agents noticed only one piece of luggage in the car and that none of the occupants

had ski equipment, parkas or winter clothing. The combination of Mares’s

answers and her unusual circumstances caused Border Patrol agents to become

suspicious. 

After an inspection of the undercarriage of her vehicle revealed tool marks

indicating that the gas tank had recently been removed or serviced, the Border

Patrol agents requested, and Mares gave, consent to a search of her gas tank. The

search revealed three metal canisters packed with 32.5 kilograms of marijuana

and Mares was arrested. Mares told the agents she was completely unaware of the

marijuana in the gas tank and was “stunned” by its discovery despite the fact that

the containers occupied almost eighty percent of the gas tank. (R. Vol. IV at

151.) 

On questioning, Mares said she did not know where Dominguez lived and

that she “[thought she knew] his cell phone number” even though they had been

“going out for about three weeks” and she was supposed to meet him in Ruidoso

with his car. (Id. at 78.) After arresting Mares, authorities attempted to locate

Dominguez using information from the bill of sale Mares provided. This effort

was fruitless because none of the information on the bill of sale could be verified,

and much of it, including Dominguez’s Social Security Number, was fraudulent. 
1 The United States disclosed it intended to introduce evidence subject to

Fed. R. Evid. 404(b) over two months prior to trial.

-4-

While awaiting trial, Mares was again arrested by the Border Patrol, this

time at the Ysleta Port of Entry in El Paso, Texas, on December 11, 2003. As in

her first arrest, three metal canisters of marijuana were found in the gas tank of

the vehicle she was attempting to drive into the United States. This time, the

canisters contained 43 kilograms of marijuana. Mares claimed that a Mr.

Alejandro Dominguez had forced her into transporting this second load of

marijuana after she confronted him about “us[ing]” her for the first load. 

However, she also admitted to Border Patrol agents that the same people who

“hired” her for the first load had forced her to transport this second load. (R. Vol.

IV at 38, 51-52, 116–17.) Mares pleaded guilty to this second offense.

The Trial. Mares maintained her innocence as to the first load of

marijuana, and the case proceeded to trial in November 2004. Just before trial,

Mares filed a motion in limine seeking to prevent the United States from

introducing evidence of her second arrest under Fed. R. Evid. 403 and 404(b).1

The district court ruled that the evidence was admissible under Rule 404(b): 

[It is] offered for proper purpose under Rule 404(b), to show, among

other things, the common plan, knowledge, intent and absence of

mistake or accident . . . . It’s very similar, and the two incidences are

very similar in nature in terms of the area in which they occurred,

how the marijuana was packaged in metal containers, where they were

in the vehicles and other things. . . . Obviously, it is prejudicial, but I
-5-

don’t think it is unfairly prejudicial to the extent that the probative

value is substantially outweighed . . . I will, if the defendant requests,

give appropriate instruction to the jury. . . 

(R. Vol. IV at 7.) A jury found Mares guilty of possession with intent to

distribute less than 50 kilograms of marijuana in violation of 21 U.S.C. §§

841(a)(1) and (b)(1)(D). 

Sentencing. The presentence report calculated Mares’s base offense level

as 22 on the basis of the amount of marijuana involved. Upon the government’s

informal objection, the probation officer recommended increasing Mares’s

offense level by two for obstruction of justice because of her false testimony at

trial. Mares objected to this enhancement and also argued that she should have

received a minor role adjustment under USSG § 3B1.2.

At her sentencing hearing, the district court found that Mares perjured

herself at trial and, accordingly, increased her sentence by two levels for

obstruction of justice. The court also found that Mares was not entitled to a

minor role adjustment because of the extensive planning involved and the

distance she was willing to travel to traffic drugs. As a result, Mares’s total

offense level was 24 and her criminal history category I, resulting in a guideline

recommendation of 51-63 months. The district court sentenced Mares to 51

months in prison to be followed by three years supervised release.

II. Analysis
-6-

Mares argues the district court erred in two ways. First, she claims the

court improperly admitted evidence at trial from her second arrest for drug

transportation. Her second claim is that the court improperly rejected her role as

a minor participant and then enhanced her sentence because it determined she

committed perjury at trial. We disagree with both of her claims.

A. Evidence of Subsequent Act under Rule 404(b)

We review the district court’s admission of evidence under Fed. R. Evid.

404(b) for abuse of discretion. United States v. Shumway, 112 F.3d 1413, 1419

(10th Cir. 1997). We will not reverse a district court’s ruling if “it fall[s] within

the bounds of permissible choice in the circumstances” and is not “arbitrary,

capricious or whimsical.” Id.

1. Rule 404(b) Generally

Federal Rule of Evidence 404(b) provides:

Evidence of other crimes, wrongs or acts is not admissible to prove the

character of a person in order to show action in conformity therewith. 

It may, however, be admissible for other purposes, such as proof of . . .

intent, . . . plan, knowledge, . . . or absence of mistake.

Our case law instructs courts to consider four factors in weighing the

admissibility of evidence under Rule 404(b): (1) whether the evidence is offered

for a proper purpose, (2) its relevancy, (3) that the probative value of the evidence

is not substantially outweighed by its prejudicial effect, and (4) a limiting

instruction is given if the defendant so requests. See Huddleston v. United States,
-7-

485 U.S. 681, 691 (1988); United States v. Zamora, 222 F.3d 756, 762 (10th Cir. 

2000).

Evidence is admitted for a proper purpose if allowed for one or more of the

enumerated purposes in Rule 404(b). It is relevant if it tends to prove or disprove

one of the elements necessary to the charged offense. See Fed. R. Evid. 401. The

danger of unfair prejudice resulting from the evidence’s admission must not

substantially outweigh the probative value of the evidence under the balancing

test of Fed. R. Evid. 403. See United States v. Tan, 254 F.3d 1204, 1211–12

(10th Cir. 2001) (in order for evidence to be inadmissible under Rule 403 the

evidence’s unfair prejudice must do more than “damage the [d]efendant’s position

at trial,” it must “make[] a conviction more likely because it provokes an

emotional response in the jury or otherwise tends to affect the jury’s attitude

toward the defendant wholly apart from its judgment as to his guilt or innocence

of the crime charged”). The limiting instruction must caution the jury to consider

the evidence only for the limited purposes for which it is admitted and not as

probative of bad character or propensity to commit the charged crime. 

2. Subsequent Acts

It is settled in the Tenth Circuit that evidence of “other crimes, wrongs, or

acts” may arise from conduct that occurs after the charged offense. Our cases

have held that “[r]egardless of whether 404(b) evidence is of a prior or
-8-

subsequent act, its admissibility involves a case-specific inquiry that is within the

district court’s broad discretion.” United States v. Olivo, 80 F.3d 1466, 1469

(10th Cir. 1996). Where the uncharged acts show motive, intent, or knowledge,

they are admissible “whether the acts involved previous conduct or conduct

subsequent to the charged offense, as long as the uncharged acts are similar to the

charged crime and sufficiently close in time.” United States v. Zamora, 222 F.3d

756, 762 (10th Cir. 2000).

Subsequent acts evidence is particularly relevant when a defendant’s intent

is at issue. In Olivo, for example, the defendant was charged with arranging for

the transportation of large amounts of marijuana on board his employer’s trucking

fleet. 80 F.3d at 1468. The marijuana was compressed, wrapped, dipped in tar,

rewrapped and secreted in grocery boxes. Prior to trial, the defendant drove a

vehicle containing a large amount of marijuana, and the marijuana was also

compressed into blocks, wrapped several times and concealed inside grocery

boxes. Although the subsequent act occurred over one year after the charged

offense, we held that evidence of this crime was properly admitted under Rule

404(b) to show intent and planning. We further held that the length of time

between the two incidents did not undermine its probative value. The events were

of sufficient similarity to justify the district court’s admission of the evidence

under an abuse of discretion standard.
-9-

We have routinely upheld the admissibility of subsequent acts evidence in

other cases. See, e.g., Zamora, 222 F.3d at 762 (evidence of subsequent robbery

properly admitted under 404(b) to prove knowledge, intent and lack of mistake);

United States v. Gutierrez, 696 F.2d 753, 755 (10th Cir. 1982) (evidence of

robbery five weeks after charged robbery properly admitted under Rule 404(b) to

prove identity); United States v. Abreu, 962 F.2d 1425 (10th Cir. 1992) (evidence

of defendant’s subsequent possession of cocaine relevant to prove intent in drug

trafficking case). 

Although generally admissible, subsequent conduct, just as prior conduct,

must share similarity with the charged crime. Zamora, 222 F.3d at 762. It need

not be identical. Gutierrez, 696 F.2d at 755. Similarity may be demonstrated

through “physical similarity of the acts or through the ‘defendant's indulging

himself in the same state of mind in the perpetration of both the extrinsic offense

and charged offenses.’” Zamora, 222 F.3d at 762 (quoting United States v. Queen,

132 F.3d 991, 996 (4th Cir. 1997)).

We have identified a number of non-exclusive factors in assessing

similarity: (1) whether the acts occurred closely in time. See Olivo, 80 F.3d at

1468; see also United States v. Bonnett, 877 F.2d 1450, 1461 (10th Cir. 1989)

(reviewing the admission of subsequent bad acts under Rule 404(b) and

explaining that “[t]he closeness in time and the similarity in conduct [are] matters
-10-

left to the trial court, and [its] decision will not be reversed absent a showing of

abuse of discretion”); (2) geographical proximity, see Zamora, 222 F.3d at

762–63 (evidence of robbery of restaurant in same town as charged attempted

bank robbery); (3) whether the charged offense and the other acts share similar

physical elements, see id.; see also Gutierrez, 696 F.2d at 755 (subsequent

robbery similar to charged robbery in that defendant in both instances drove

getaway car and used her children as “cover”); and (4) whether the charged

offense and the other acts are part of a common scheme, see United States v.

Becker, 230 F.3d 1224, 1232-33 (10th Cir. 2000) (drug defendant’s prior

convictions for methamphetamine possession and distribution not admissible

under Rule 404(b) in part because the prior acts lacked a common scheme with

the charged offense of methamphetamine production).

With these principles in mind, we turn to Mares’s argument.

3. Application

Mares’s argument at trial was that she was a victim of trickery when she

was arrested in 2002. She claimed her friend, Alejandro Dominguez, duped her

into unknowingly carrying drugs across the Mexican/American border. 

Consequently, she maintains the subsequent arrest contributed nothing to the

jury’s determination of the elements of the prior charged crime. She also argues

the subsequent conduct was too far removed in time and place to satisfy the
-11-

requirements of Rule 404(b). In response, the government argues the evidence of

Mares’s December 2003 arrest satisfies at least three of the purposes articulated

in Fed. R. Evid. 404(b): (1) it shows Mares’s knowledge of the marijuana

canisters found in her gas tank in December 2002, (2) it establishes that

transportation of marijuana in her gas tank was part of a plan or conspiracy to

smuggle drugs, and (3) it tends to show the earlier conduct was not a mistake or

accident. The government also argues the time and place of the two incidents are

close enough to satisfy Rule 404(b). We agree.

The first Huddleston factor—proper purpose—is easily met here. The

evidence tends to show Mares willingly and knowingly participated in a drug

trafficking scheme. Her central defense to the charges was lack of knowledge

that the car contained drugs at the time of the 2002 arrest. The 2003 arrest,

however, rebuts her version of events because it shows conduct bearing the same

hallmarks of the earlier border crossing: the drugs were smuggled in the same

secretive way, in both cases she claimed to be borrowing a car for which no

registration was available, she had a prepared cover story regarding her plans in

the United States, and finally in both cases she claimed Alejandro Dominguez was

the mastermind. In light of these identifying circumstances, the district court did
2

 Mares relies on a Seventh Circuit case to argue that subsequent narcotics

activity is particularly irrelevant to prior drug crimes. United States v. Betts, 16

F.3d 748 (7th Cir. 1994). Betts does not advance her argument: the court

specifically said that “when a defendant raises the defense that he was duped on

the first occasion, evidence of subsequent conduct may be admissible to establish

that his conduct was not inadvertent but knowing.” Id. at 759.

3 Mares also claims her conduct bears no “signature quality” which sets it

apart from the hundreds, if not thousands, of drug arrests at the Mexican border. 

While this may be true, her conduct contains other indicia of similarity that make

it admissible for the applicable purposes under Fed. R. Evid 404(b). “Signature

quality” evidence, see United States v. Oberle, 136 F.3d 1414, 1419 (10th Cir.

1998) is often introduced to show identity. Evidence under Rule 404(b) need only

be of a “signature quality” when being introduced for the purpose of proving

identity by modus operandi. In this case, no one disputes that Mares committed

both smuggling crimes.

-12-

not err in finding the subsequent similar act was offered for a proper purpose

under Rule 404(b).2

The second Huddleston factor is relevance. This factor is also easily

satisfied. In addition to the 2002 arrest’s relevance to Mares’s knowledge or

plan, she admitted after her 2003 arrest that the same people who had paid her to

transport the load of marijuana in 2002 forced her to transport the 2003 load. The

evidence thus tends to show Mares (1) knew marijuana was in her gas tank in

2002, (2) made no mistake about carrying this load of illegal drugs in 2002, and

(3) was party to a plan to transport the drugs in her vehicle’s gas tank. Its

similarity is obvious.3

The third Huddleston factor requires the court to balance the probative

value of the evidence against its prejudicial effect under Fed. R. Evid. 403. 
-13-

Mares contends that the 2003 offense occurred too long after the charged

offense—one year—and was too geographically distant to be of much probative

value. Our cases make clear that the degree to which factors such as temporal

distance and geographical proximity are important to a determination of the

probative value of similar acts will necessarily depend on the unique facts of each

case’s proffered evidence. Here, the subsequent act is nearly identical to the prior

act, and, combined with Mares’s admission about the circumstances of the

subsequent conduct, allow a fact finder to draw obvious conclusions bearing on

Mares’s defense that she was duped into carrying the drugs. The “exclusion of

evidence under Rule 403 . . . is an extraordinary remedy and should be used

sparingly.” United States v. Tan, 254 F.3d 1204, 1211 (10th Cir. 2001). While

the evidence was “prejudicial” to Mares in the sense that it rebutted her theory of

defense, such is the nature of evidence establishing an element of the charged

crime. The district court did not err in finding its probative value highly relevant

and therefore admissible. 

The final factor in Huddleston allows the defendant to receive a limiting

instruction upon request. Here, the court offered and issued a limiting instruction

approved by Mares’s counsel.

In sum, the district court properly found the evidence satisfied all four

Huddleston factors. The evidence was thus properly admitted under Rule 404(b).
-14-

B. Sentencing Error

Since United States v. Booker, 543 U.S. 220 (2005) we review sentences

for reasonableness. Mares argues that the district court committed two errors at

her sentencing. First, she claims it erred in calculating the applicable guideline

range by wrongfully denying her a reduction in sentence for her minor role in the

drug smuggling scheme, and improperly increasing her sentence for obstruction of

justice based on her perjury at trial. Second, she contends the 51-month sentence

imposed was not reasonable in light of 18 U.S.C. § 3553(a). We reject both

arguments. 

1. Adjustments/Guideline Error

In considering whether the district court erred in its calculation of the

applicable Guideline range, we review the district court’s factual findings for

clear error, United States v. Kristl, 437 F.3d 1050, 1054 (10th Cir. 2006). We

review its legal conclusions regarding the application of the guidelines de novo. 

Id.

Minor Participant. The district court found that Mares was not entitled to a

two-level downward departure as a minor participant in the drug conspiracy. The

minor participant adjustment is available for:

a defendant who is convicted of a drug trafficking offense, whose role

in that offense was limited to transporting or storing drugs and who is

accountable . . . only for the quantity of drugs the defendant personally

transported or stored. 
-15-

USSG § 3B1.1, cmt. n. 3(A). According to Mares, she was only a low-level

courier and did not play a major role in the drug ring; therefore, she should have

received the adjustment. 

The district court found to the contrary: 

[T]he distance is greater than the other cases in which I give minor

participation [to a defendant on the basis of serving as a mere “mule” in a

drug-trafficking scheme]. If they’re simply bringing it across the border

and delivering it not further than Las Cruces, for example, to my mind,

they’re doing a very short turn-around trip for which they’re usually not

paid very much . . . . In this instance you have the fact of the defendant

bringing along a friend and two children. . . . I do think in this instance

there is more planning than is normal, and for that reason I don’t think that

minor participation is appropriate. 

(R. Vol. III at 15–16.) When combined with the evidence that she had been

“hired” for the 2002 drug run, the court did not err in finding the minor

participant adjustment inapplicable.

Obstruction of Justice. Mares also argues that the district court erred by

increasing her offense level by two levels for obstruction of justice. The

Guidelines provide for a two-level increase if the defendant:

. . . (A) willfully obstructed or impeded, or attempted to obstruct or

impede, the administration of justice during the course of the

investigation, prosecution, or sentencing of the instant offense of

conviction, and (B) the obstructive conduct related to (i) the defendant’s

offense of conviction and any relevant conduct; or (ii) a closely related

offense.

USSG § 3C1.1. 
4

In order to establish that a defendant committed perjury, the district court

must find that (1) the defendant gave false testimony while under oath, (2)

concerning a material matter, and (3) the false testimony was willful and not the

result of confusion, mistake or faulty memory. United States v. Chavez, 229 F.3d

946, 955 (10th Cir. 2000). The district court properly found all three elements. 

-16-

The district court found that Mares had committed extensive perjury at trial

in denying her role in the drug smuggling scheme.4

 Its conclusion rested on a

number of observations gleaned from Mares’s trial testimony. In particular, the

court found that Mares was more deeply involved in the scheme than she

suggested, given the many discrepancies in her testimony. For example, Mares

lied at trial in a number of ways, claiming: (1) she did not know there was

marijuana in the vehicle, (2) Alejandro Dominguez threatened her into carrying

the 2003 load despite her initial contention that she did not know there was

anything in her gas tank, (3) she was not hired to drive the first load of marijuana,

(4) she did not notice anything strange about the gas gauge on the car she was

driving even though approximately eighty percent of the gas tank’s volume was

occupied by marijuana, and (5) she was not party to a plan to conceal over 32

kilograms of marijuana in the car’s gas tank despite the fact that she was arrested

with marijuana hidden in her gas tank in 2003. 

Under the sentencing guidelines, perjury can support an enhancement for

obstruction of justice. USSG § 3C1.1, cmt. n. 4(b); United States v. SalazarSamaniega, 361 F.3d 1271, 1275-76 (10th Cir. 2004). The jury rejected Mares’s
-17-

testimony that she was unaware her car contained drugs at the time of the 2002

arrest. The district court did not err in finding she wilfully obstructed justice at

her trial by committing perjury, and as such properly increased her guideline

offense level by two. 

2. Reasonableness under 18 U.S.C. § 3553(a)

Mares’s last argument is that the 51-month sentence imposed is

unreasonable in light of the factors set out in 18 U.S.C. § 3553(a). We have held

that a sentence within a correctly calculated guideline range is entitled to a

presumption of reasonableness. Kristl, 437 F.3d at 1054.

At sentencing, Mares made several blanket policy arguments regarding the

general unreasonableness of guideline sentences in drug cases, but did not

articulate exactly how any one of the seven § 3553(a) factors should be applied to

require a different sentence. Mares did argue that her lack of prior criminal

history entitled her to the “safety valve” provision of 18 U.S.C. § 3553(f),

reflected at USSG § 3B1.2. In arguing for a departure under the guidelines Mares

also noted that she has two young children, one of whom has health problems, and

that she herself has medical problems. We will construe her presentation of these

circumstances as an argument for an adjustment based on her personal “history

and characteristics” under § 3553(a)(1).
-18-

 It is apparent from the transcript of the sentencing proceedings that the

district court considered Mares’s personal history and familial obligations when it

elected to impose a guideline sentence at the very bottom of the applicable range. 

We will “not demand that the district court recite any magic words to show us that

it fulfilled its responsibility to be mindful of the factors that Congress has

instructed it to consider.” United States v. Contreras-Martinez, 409 F.3d 1236,

1242 (10th Cir. 2005). While the district court may have been able to justify a

nonguideline sentence on the basis of Mares’s personal history and

characteristics, including her familial obligations, it was not obligated to do so. 

This is especially true in light of Mares’s failure to explicitly present her family’s

situation in terms of § 3553(a)(1). We cannot say the district court imposed an

unreasonable sentence in failing to impose a sentence outside the applicable

guideline range.

III. Conclusion

For the foregoing reasons, we hold that the district court properly admitted

evidence of Mares’s subsequent acts under Fed. R. Evid. 404(b) and imposed a

reasonable sentence under 18 U.S.C. 3553(a).