FILED

United States Court of Appeals

Tenth Circuit

July 26, 2017

Elisabeth A. Shumaker

Clerk of Court

PUBLISH

UNITED STATES COURT OF APPEALS

TENTH CIRCUIT

UNITED STATES OF AMERICA,

Plaintiff - Appellee,

v. No. 15-1490

HAROLD ARTHUR HENTHORN,

Defendant - Appellant.

APPEAL FROM THE UNITED STATES DISTRICT COURT

FOR THE DISTRICT OF COLORADO

(D.C. NO. 1:14-CR-00448-RBJ-1)

O. Dean Sanderford, Assistant Federal Public Defender (Virginia L. Grady,

Federal Public Defender, with him on the briefs), Office of the Federal Public

Defender, Districts of Colorado and Wyoming, Denver, Colorado, for Appellant.

J. Bishop Grewell, Assistant United States Attorney (Robert C. Troyer, Acting

United States Attorney, with him on the brief), Office of the United States

Attorney, Denver, Colorado, for Appellee.

Before TYMKOVICH, Chief Judge, SEYMOUR, and KELLY, Circuit Judges.

TYMKOVICH, Chief Judge.

This case presents us with the difficult issue of whether a district court

presiding over a murder trial abused its discretion in admitting evidence of prior,
similar incidents, including whether the defendant killed his second wife in

circumstances similar to those that led to the death of his first wife. 

We affirm. The district court did not abuse its discretion in admitting prior

similar conduct. The court fully explained, and we agree, that the evidence was

properly admitted under Federal Rule of Evidence 404(b), was relevant, and was

not substantially outweighed by unfair prejudice.

I. Background

In September 2012, Harold Henthorn’s second wife, Toni,1 died after

falling more than 100 feet from a cliff in Rocky Mountain National Park. She fell

in a remote location with poor cellular service and no nearby aid stations. 

Henthorn first called 911 around 6:00 pm, but—due to the remoteness of the

location—by the time the first ranger arrived on the scene, it was after 8:00 pm

and Toni was dead. After an investigation, Henthorn was charged with and tried

for first-degree murder on the government’s theory that he, with premeditation

and malice aforethought, pushed Toni over the cliff to her death.

The evidence presented at trial provides a basic timeline of events, starting

in the early afternoon when Henthorn and Toni set out for their hike as part of a

celebration of their twelfth wedding anniversary. Sometime before 3:30 pm, the

1

 Because this opinion refers to two of Henthorn’s wives, both of whom

took his surname upon marriage, we refer to them by their first names to avoid

any ambiguity.

-2-
couple left the established trail. Photographs around this time show the couple

eating lunch atop a scenic cliff overlook. Additional photographs indicate that

the couple continued off trail and found a cliff below their lunch spot around

4:45 pm. It is estimated that Toni fell from that cliff shortly before 5:15 pm. 

Henthorn estimates it took him forty-five minutes to call 911 after Toni’s fall,

including fifteen minutes to reach her body and thirty minutes to assess and move

her, return to cellular coverage, and call 911. The first 911 call occurred at

5:54 pm. At 6:16 pm, Henthorn sent a text message to Toni’s brother, Barry

Bertolet, indicating that Toni was in critical condition after falling from a rock,

EMTs were coming, Barry should catch the next flight, and his cell phone battery

was low. Henthorn exchanged several conversations with 911 dispatchers

between the time of his first call at 5:54 pm and when the first EMT ranger

arrived at the scene around 8:00 pm, examined Toni’s body, and reported her

death.

An investigation of the incident raised a number of questions about

Henthorn’s version of events. For example, Henthorn told a ranger that he and

Toni initially planned to hike the Bear Lake trail, a half-mile of paved,

handicapped-accessible walking with no elevation gain. He explained that they

switched to Deer Mountain trail at the last second to avoid crowds. Deer

Mountain trail is a three-mile hike climbing 1,200 feet from its trailhead to its

10,200-foot summit, and thus an odd choice for Toni, who had undergone three

-3-
knee surgeries and whose chronic injuries left her unable to ski. Henthorn also

feigned unfamiliarity with the park and told a ranger that he had made only one

earlier scouting trip to the park, but phone records revealed he visited the park at

least eight or nine times in the six weeks before Toni’s death. And while

Henthorn described their venture away from the Deer Mountain trail to the offtrail lunch spot and lower cliff (where Toni fell) as a spontaneous decision to get

away from crowds, find a romantic spot, or see wild turkeys or deer, investigators

later discovered that he was quite familiar with the precise area where Toni died. 

For instance, Henthorn reported a white sheet adorned a cliff near Toni’s fall, but

that sheet had actually been removed by Park Service the week before her fall. 

And the Park Service found a detailed, annotated map of the park in Henthorn’s

car with notes, highlighting, and a pink “X” marking the spot on the map where

Toni fell.

Evidence of Henthorn’s communications during and after the incident was

also troubling. For example, Henthorn reported certain vital signs (e.g., pulse and

respirations), but the vitals he provided were inconsistent with Toni’s injuries.2

2

 For example, during the 911 call beginning at 5:54 pm, Henthorn told the

dispatchers that Toni had a head injury, a pulse of 60–80, and respirations of 5–8

per minute. He later (sometime between 6:16 pm and 6:39 pm) told Barry, Toni’s

brother, that Toni’s pulse was 60 and respirations 5. And at 6:32 pm Henthorn

told 911 dispatchers that Toni’s breathing was shallow and he was about to start

CPR. But, given her injuries, Dr. James Wilkerson (the Larimer County coroner

and chief medical examiner, qualified by the court as an expert forensic

pathologist) estimated at trial that Toni died between 20–60 minutes after her fall,

(continued...)

-4-
During the 911 call beginning at 6:54 pm, the dispatchers attempted to coach

Henthorn through CPR but doubted he was actually performing it.3

 Less than four

2

(...continued)

see R., Vol. VII, at 530, and was therefore almost certainly dead by 6:15 pm. 

3

 Julie Sullivan (the emergency services dispatcher for the Larimer

Emergency Telephone Authority at the Estes Park Police Department) used a

“standardized protocol” to coach people through CPR over the phone and had

made “about 240” such calls before she talked with Henthorn in September 2012. 

R., Vol. VII, at 165–66, 171–73. Sullivan testified that her conversation with

Henthorn was very unusual and she identified several red flags throughout the

process. In particular, she commented,

In my experience, when I’m doing CPR with somebody, guiding them

through it, even if they are experienced people, nurses and other people

on the scene, they’re extremely out of breath. I found it unusual that he

wasn’t letting me know when he was completed with an instruction I

had given him. A lot of—you know, every other call I’ve been with,

the person wants to know immediately what to do next. Okay, I did my

30, what do I do next. What do I do next. That was very unusual, and

I didn’t feel like he was doing the CPR. Most people because of the

exertion of doing the CPR, the compressions and also giving the

breaths, it’s very exhausting. . . . I need to know when you’re complete

with it, so we can go ahead and go on to the next instruction, and he

was not letting me know after he completed every instruction I’d given

him. So I was prompting him to let me know. . . . And also we did

have an open line. On all the other CPR calls that I’ve done through

my career, I can hear them as they are doing the compressions on the

patient ‘cause it’s a lot of breathing, it’s a heavy breathing, it’s very

exhausting, and it’s hard to even get out and talk back—they have a

hard time talking with me because they are so out of breath because of

the exertion.

Id. at 174–75; see also id. at 180 (Sullivan testifying, based on her experience,

that she “did not believe that [Henthorn] was doing the CPR,” did not think he

was doing the steps with her, and was not out of breath—“That’s why I asked if

someone else was there on the scene with him. I was wondering if somebody else

was doing the chest compressions and the CPR”).

-5-
minutes into the call, Henthorn said he had to turn off his phone because his

battery was almost gone. After hanging up on the 911 dispatcher, however,

Henthorn made another twenty-two calls and sent or received ninety-eight text

messages, including multiple calls and at least sixteen text messages to a friend

asking if he could drive to pick Henthorn up from Estes Park and recommending

that the friend take a particular route. And while Toni sustained serious injuries

from the fall, the medical examiner found no signs of the abrasions, contusions,

or anterior rib fractures typically associated with the performance of CPR.4

Toni’s lipstick was not even smeared from the alleged mouth-to-mouth

resuscitation.

Finally, the investigation revealed Henthorn had taken out several large life

insurance policies on Toni’s life prior to her death and recently made himself the

beneficiary of a life insurance annuity originally naming their seven-year-old

daughter as the beneficiary.5

4

 Toni’s fall was broken by a tree at the cliff’s base, which scalped hair

and tissue from her skull. Her brain was hemorrhaging, her neck was fractured,

she had blunt force trauma to the chest, abdomen, and pelvis, her ribs were

broken and her chest deformed with her liver and lungs lacerated and bleeding,

and her skin was pale from blood loss.

5

 At the time of the incident, Henthorn held three $1.5 million life

insurance policies on Toni and a $205,000 annuity—he stood to receive more than

$4.7 million from Toni’s death. But when a ranger asked about Toni’s life

insurance, Henthorn only mentioned a $1 million policy for the couple’s daughter

and a potential $50,000 policy from a recent car purchase.

-6-
During the course of the investigation, prosecutors learned of two prior

incidents involving Henthorn and his wives. First, they became aware of the

mysterious circumstances surrounding the death of Henthorn’s first wife, Lynn, in

May 1995. Lynn died while she and Henthorn were changing a tire on the side of

the road; she was crushed under the car and died from internal injuries consistent

with traumatic asphyxiation. Prior to that incident, Henthorn had also taken out a

large life insurance policy on Lynn, but no legal action came as a result. Second,

they discovered an incident in May 2011 when Henthorn threw a heavy beam off

a deck he was repairing at the couple’s vacation cabin near Grand Lake,

Colorado. The beam struck Toni in the back of the neck and upper back, injuring

her neck.

The district court allowed the prosecution to present evidence at Henthorn’s

murder trial of the two prior incidents to rebut Henthorn’s defense that Toni’s

death was an accident. On appeal, Henthorn contends the district court erred in

admitting the evidence.

II. Analysis

Evidence of crimes, wrongs, or other acts is prohibited under the Federal

Rules of Evidence when used “to prove a person’s character in order to show that

on a particular occasion the person acted in accordance with the character.” Fed.

R. Evid. 404(b)(1). Such evidence is permitted, however, “for another purpose,

such as proving motive, opportunity, intent, preparation, plan, knowledge,

-7-
identity, absence of mistake, or lack of accident.” Fed. R. Evid. 404(b)(2). To

determine whether Rule 404(b) evidence is properly admitted, we look to the

four-part test from Huddleston v. United States, 485 U.S. 681 (1988):

(1) The evidence must be offered for a proper purpose under Rule 404(b); 

(2) The evidence must be relevant under Rule 401; 

(3) The probative value of the evidence must not be substantially

outweighed by its potential for unfair prejudice under Rule 403; and 

(4) The district court, upon request, must have instructed the jury pursuant

to Rule 105 to consider the evidence only for the purpose for which it was

admitted. See United States v. Rodella, 804 F.3d 1317, 1333 (10th Cir. 2015),

cert. denied, 137 S. Ct. 37 (2016).

Admissibility of evidence under Rule 404(b) “involves a case-specific

inquiry that is within the district court’s broad discretion.” United States v.

Mares, 441 F.3d 1152, 1157 (10th Cir. 2006) (citing United States v. Olivo, 80

F.3d 1466, 1469 (10th Cir. 1996)). We review a district court’s decision to admit

such evidence for an abuse of discretion and “will not reverse unless the district

court’s decision exceeded the bounds of permissible choice in the circumstances

or was arbitrary, capricious or whimsical.” Rodella, 804 F.3d at 1329 (citing

United States v. Nance, 767 F.3d 1037, 1042 (10th Cir. 2014)).

Before trial, the government filed a notice of Rule 404(b) evidence, stating

that it planned to introduce evidence of three prior incidents involving Henthorn,

-8-
his wives, and his former sister-in-law: (1) Lynn’s death while changing a tire in

May 1995; (2) Henthorn’s secret acquisition in 2010 of a $400,000 life insurance

policy on Grace Rishell (who was married to Lynn’s brother) in which he named

himself as the primary beneficiary; and (3) a previous injury suffered by Toni in

May 2011. The defense objected and filed a motion in limine to exclude the

evidence, primarily on the ground that it constituted improper character evidence

and was substantially more prejudicial than probative. 

To consider the issues, the district court held an extensive, two-day hearing

in which it heard evidence from ten witnesses (including seven defense

witnesses), received over thirty exhibits, and heard oral argument from both sides. 

In a subsequent eighteen-page order covering all of the Huddleston factors, the

district court ruled that the evidence of both prior incidents involving his wives

would be admitted for the limited purpose of proving planning, intent, and lack of

accident relating to Toni’s death in September 2012. The court denied the

government’s request to allow testimony regarding the life insurance policy

Henthorn took out on his former sister-in-law, finding that the incident “might be

relevant to a charge of attempting to defraud Ms. Rishell’s insurance company,

but . . . [was] not relevant to the actual crime charged” (i.e., Toni’s murder). R.,

Vol. I, pt. 1, at 237–38. The court provided limiting instructions that emphasized

the admitted evidence’s limited purpose both when the evidence was introduced at

trial and in the written jury instructions.

-9-
We address the district court’s application of each of the four Huddleston

factors in turn.

1. Factor One: Proper Purpose

The first Huddleston factor requires the evidence be offered for a proper

purpose under Rule 404(b). “Evidence is offered for a proper purpose if it is

utilized for any of the ‘other purposes’ enumerated in Rule 404(b),” United States

v. Davis, 636 F.3d 1281, 1298 (10th Cir. 2011), and that enumerated list “is

illustrative, not exhaustive,” United States v. Brooks, 736 F.3d 921, 939 (10th Cir.

2013) (citing United States v. Tan, 254 F.3d 1204, 1208 (10th Cir. 2001)). “Rule

404(b) is considered to be an inclusive rule, admitting all evidence of other

crimes or acts except that which tends to prove only criminal disposition.” 

Brooks, 736 F.3d at 949.

The government was required to prove Henthorn committed a specific

intent crime: first-degree murder requires a “willful, deliberate, malicious, and

premeditated killing.” 18 U.S.C. § 1111(a). It offered the prior acts evidence to

prove “Henthorn’s intent, motive, and plan,” and to “establish that the death of

his wife Toni was no accident.” R., Vol. I, pt. 1, at 16; id. at 22 (invoking

“intent, motive, planning, preparation, and lack of accident”). The district court

admitted the evidence to “rebut[] the defense of accident or to show[] plan and

intent.” Id. at 231, 237. These purposes are specifically contemplated by Rule

404(b) and are plainly proper. See Fed. R. Evid. 404(b)(2) (listing “motive,

-10-
opportunity, intent, preparation, plan, knowledge, identity, absence of mistake, or

lack of accident” (emphases added)). Henthorn does not argue otherwise.6

The first Huddleston factor is satisfied.

2. Factor Two: Relevance

The second Huddleston factor requires the evidence be relevant under Rule

401. Evidence is relevant if: (1) “it has any tendency to make a fact more or less

probable than it would be without the evidence”; and (2) “the fact is of

consequence in determining the action.” Fed. R. Evid. 401. In other words,

“[r]elevant evidence tends to make a necessary element of an offense more or less

probable.” Davis, 636 F.3d at 1298.

a. Similarity

The lynchpin of Huddleston relevance is similarity. “To determine the

relevance of a prior bad act, we look to the similarity of the prior act with the

charged offense, including their temporal proximity to each other.” Brooks, 736

F.3d at 940. Uncharged acts are admissible “as long as the uncharged acts are

similar to the charged crime and sufficiently close in time.” Mares, 441 F.3d at

1157 (citing United States v. Zamora, 222 F.3d 756, 762 (10th Cir. 2000)). 

“[T]he degree to which factors such as temporal distance and geographical

6

 To the extent, if any, that Henthorn disputes whether the district court

admitted the evidence for a proper purpose under Rule 404(b)—namely, whether

the evidence was improperly admitted to show Henthorn’s alleged propensity to

commit murder—his arguments hinge on contentions of relevance that we address

under the second Huddleston factor.

-11-
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.” 

Mares, 441 F.3d at 1159. But even so, acts “quite remote to the crime[] charged

have frequently been deemed by us and our sister circuits to be relevant if they

were sufficiently similar to those crimes.” United States v. Watson, 766 F.3d

1219, 1240 (10th Cir. 2014). In other words, there is “no absolute rule regarding

the number of years that can separate offenses.” Id. (citations omitted). Instead,

this court “applies a reasonableness standard and examines the facts and

circumstances of each case.” Id. (citations omitted).

As the district court concluded, the prior incidents here were both

extraordinarily similar to the charged offense.

i. Lynn’s Death

Henthorn’s first wife, Lynn, died from internal injuries consistent with

traumatic asphyxiation after being pinned under a vehicle. The incident occurred

in May 1995 when she and Henthorn were changing a tire on a remote highway

approximately thirty miles from their home in southwest Denver. The couple

pulled over on a gravel slope alongside the road in a heavily forested area. It was

dark and there was no cellular service. There were no houses nearby and the

nearest hospital was a forty-minute drive away.

Several suspicious facts about the incident are noteworthy. For example,

the tire the couple stopped to change was not flat, but merely low, and was

-12-
measured at 15 out of 44 pounds of pressure (i.e., approximately 34 percent). The

spare tire they sought to replace it with was measured at only 4 pounds more (i.e.,

19 out of 44 pounds of pressure, or approximately 43 percent). Other tires on the

vehicle were also low, inflated between 27–30 out of 44 pounds of pressure (i.e.,

approximately 61–68 percent). A local mechanic coincidentally drove by the

couple around 9:30 pm and asked the Henthorns if they needed any help. Even

though Henthorn had only a small flashlight and would later claim he did not

know how to change a tire, he declined the mechanic’s offer to shine his

headlights on the scene or otherwise help change the tire.

Half an hour later, around 10:00 pm, Henthorn flagged down another car

and told the occupants the car had fallen on top of his wife. They drove back up

the road to try to find a house and call 911 but, when they could not find a phone,

returned to the scene to try to help. Two men were able to lift up the car and free

an unconscious Lynn. Then, Henthorn angrily screamed at them not to touch her. 

Over Henthorn’s objections, they started CPR and got her breathing again. 

Meanwhile, another passenger left the scene again, to try to find a phone, and

returned with blankets after finding someone to call 911. Emergency vehicles

eventually arrived at the scene and Lynn was airlifted to a nearby hospital but

died in surgery due to internal injuries. 

Henthorn later told inconsistent stories about the incident. For example,

Henthorn told an emergency responder that Lynn was changing the tire, but told

-13-
others that he was the one changing the tire. He told officers he used boat jacks

to prop up the car because he had tried the regular jack but could not get it to

work even after he lubricated it. No lubricant or oil was found at the scene. 

Henthorn also suggested that he got Lynn out from under the car and started CPR

(without any mention of the passersby who stopped to help and were the ones to

perform CPR), and he vacillated between whether he and Lynn were going to, or

coming from, dinner. When law enforcement asked Henthorn whether Lynn’s life

was insured, he disclosed only one of the multiple life insurance policies he

would collect on. Henthorn ultimately collected $600,000 in life insurance,

including proceeds from a policy that went into effect only two and a half months

before Lynn’s death and from an accidental death rider that doubled the benefit

from $150,000 to $300,000 in the event Lynn died in an accident.

 A couple days after the incident, one of the good samaritans who stopped to

help called law enforcement to voice her suspicions and ask if Henthorn had been

arrested in connection with Lynn’s death. While law enforcement briefly

investigated Lynn’s death as a suspicious incident, investigators eventually

determined her death was an accident despite the unusual circumstances. For

example, even though a sheriff’s deputy photographed a suspicious shoe print

atop the car’s fender (potentially suggesting that the car had been pushed off,

rather than fallen from, the jacks) and investigators took a photograph of

-14-
Henthorn’s shoes for comparison purposes, that comparison was never made. The

investigators also never challenged Henthorn’s inconsistent statements.

ii. Toni’s Injury

In May 2011, Henthorn’s second wife, Toni, suffered a neck injury when

she was struck in the back of the neck and upper back with a large wooden beam. 

The incident occurred when she and Henthorn were staying at their cabin near

Grand Lake, Colorado. It was dark and their secluded cabin was surrounded by

trees on three sides.

Several facts about the Grand Lake deck incident raise suspicion. For

example, it was around 10:00 pm at night but Henthorn was allegedly doing

construction work or cleaning on the deck of the cabin. Henthorn later told

inconsistent stories about the incident. For example, Henthorn told the

paramedics he threw the beam that hit Toni, but told an emergency room doctor

that the beam had merely fallen off the deck and hit her. He also told a friend

that he dropped the beam on Toni when he slipped from a ladder that she was

holding. A nurse’s note in Toni’s file indicates that Toni was under the deck,

holding a flashlight for Henthorn when the beam fell. And in one account, given

to friends he called to come and watch his and Toni’s daughter (who was asleep

inside the cabin), Henthorn suggested Toni was cleaning up around the deck and

had just bent down when a piece of lumber fell off the deck and hit her. If she

had not bent down, the beam would have presumably hit her in the head instead of

-15-
the neck and back. But when the friends arrived at the cabin that night to watch

the Henthorns’ daughter, they did not see any lumber on the deck. 

Prior to the incident, Henthorn held four $1.5 million life insurance policies

on Toni but cancelled one of the policies—the second of two with the same

insurance company, American General—in February 2011, three months before

the injury. One month before the injury, in April 2011, Henthorn made himself

the beneficiary of a $205,000 life insurance annuity bought by Toni’s parents for

the Henthorns’ young daughter.

At the time, medical personnel deemed the incident an accident. No one,

including Toni, voiced any suspicions that Henthorn intended to injure her and

there were no police reports or activity.

* * *

Each incident, including Toni’s death, occurred in a remote location which

impeded communications, delayed emergency responders, and reduced the

likelihood of accidental witnesses. Indeed, Henthorn was always the only witness

at the time of injury. And in the aftermath of each incident, Henthorn told

inconsistent stories about what happened. Although there is a seventeen-year gap

between his first wife’s death and Toni’s, the temporal distance is not per se

disqualifying,7

 and does not overshadow the marked similarities between the

7

 See, e.g., United States v. Watson, 766 F.3d 1219 (10th Cir. 2014) (ten to

seventeen years); United States v. Roberts, 185 F.3d 1125 (10th Cir. 1999)

(continued...)

-16-
incidents. Henthorn’s first wife, Lynn, died after thirteen years of marriage to

Henthorn. His second wife, Toni, died after twelve years of marriage. Henthorn

lied about the applicable life insurance policies and collected significant sums of

life insurance proceeds from each death. Over their respective family’s

objections, he also had each woman’s body quickly cremated and spread their

ashes at the same spot on Red Mountain near Ouray, Colorado.

b. Independence from Character Inferences

Evidence’s relevance cannot “depend on a defendant likely acting in

conformity with an alleged character trait” or require the jury to draw a “chain of

inferences dependent upon [a] conclusion” about the defendant’s character. See

United States v. Commanche, 577 F.3d 1261, 1267, 1269 (10th Cir. 2009). But

all this is “not to say that other-act evidence must be excluded whenever a

propensity inference can be drawn; rather, Rule 404(b) excludes the evidence if

its relevance to ‘another [proper] purpose’ is established only through the

forbidden propensity inference.” Rodella, 804 F.3d at 1333. 

7

(...continued)

(sixteen years); United States v. Meacham, 115 F.3d 1488 (10th Cir. 1997)

(twenty-five to twenty-nine years); United States v. Wacker, 72 F.3d 1453 (10th

Cir. 1995) (thirteen years); see also, e.g., United States v. Luger, 837 F.3d 870

(8th Cir. 2016) (twenty-five years); United States v. Sterling, 738 F.3d 228 (11th

Cir. 2013) (fifteen years); United States v. Rodriguez, 215 F.3d 110 (1st Cir.

2000) (fifteen years); United States v. Hernandez-Guevara, 162 F.3d 863 (5th Cir.

1998) (eighteen years); United States v. Hadley, 918 F.2d 848 (9th Cir. 1990)

(fifteen years).

-17-
Evidence remains admissible even if it has the potential “impermissible

side effect of allowing the jury to infer criminal propensity,” so long as the jury

“[i]s not required to make any such inferences in order to also” find wilfulness or

intent. See id. at 1333–34 (emphasis added). For example, consider our decision

in United States v. Moran, 503 F.3d 1135 (10th Cir. 2007). There, the district

court presiding over defendant Moran’s trial for being a felon in possession of a

firearm allowed the government to present evidence of Moran’s prior felon-inpossession conviction. See id. at 1138–39. While the use of Moran’s prior

conviction to help prove the only challenged element of the charged offense (i.e.,

that Moran “knowingly possessed” the firearm) “involve[d] a kind of propensity

inference (i.e., because he knowingly possessed a firearm in the past, he

knowingly possessed the firearm in the present case),” we explained that the

inference did “not require a jury to first draw the forbidden general inference of

bad character or criminal disposition.” Id. at 1145. Instead, the inference was

“specific” and “rest[ed] on a logic of improbability that recognizes that a prior act

involving the same knowledge decreases the likelihood that the defendant lacked

the requisite knowledge in committing the charged offense.” Id. 

Likewise, the use of the prior incidents here rests on a logic of

improbability that recognizes that prior incidents involving similar circumstances

decrease the likelihood that Henthorn lacked the requisite intent, motive, and plan

-18-
in committing the charged offense. Indeed, the prior incidents make it more

likely that the charged offense was the product of design, rather than an accident.8

In asserting that the evidence is irrelevant, Henthorn relies on our decision

in Commanche, where we reversed the district court’s decision to admit Rule

8

 Henthorn and the government spar over whether the chain of logic

supporting admission of the prior incidents is one of relevance or character. This

logic may be—but is not necessarily—viewed as an application of the so-called

“doctrine of chances.” The doctrine of chances relies on objective observations

about the probability of events and their relative frequency, and the improbability

of multiple coincidences. As explained by the Seventh Circuit in United States v.

York, 933 F.2d 1343 (7th Cir. 1991), the doctrine “tells us that highly unusual

events are highly unlikely to repeat themselves . . . . The man who wins the

lottery once is envied; the one who wins it twice is investigated.” Id. at 1350. 

Although this court has never explicitly endorsed the doctrine of chances, we

have acknowledged the doctrine in upholding the relevance of prior act evidence

to prove specific intent in a criminal drug trafficking case. See United States v.

Cherry, 433 F.3d 698, 701–02 (10th Cir. 2005). For academic analysis and

criticism of the doctrine, see generally Edward J. Inwinkelried, An Evidentiary

Paradox: Defending the Character Evidence Prohibition by Upholding a NonCharacter Theory of Logical Relevance, the Doctrine of Chances, 40 U. Rich. L.

Rev. 419 (2006); Andrew J. Morris, Federal Rule of Evidence 404(b): The

Fictitious Ban on Character Reasoning from Other Crime Evidence, 17 Rev.

Litig. 181 (1998).

We are inclined to agree with the district court that the doctrine of chances

“is merely one name to call a common sense observation that a string of

improbable incidents is unlikely to be the result of chance,” an observation

recognized by the Supreme Court in Lisenba v. California, 314 U.S. 219, 227

(1941) (invoking the “widely recognized principle that similar but disconnected

acts may be shown to establish intent, design, and system”). Indeed, Lisenba

involved testimony concerning the mysterious death of the defendant’s former

wife, which was admitted as evidence in a trial against the defendant for the

murder of his second wife “in a manner to give the appearance of accident” and

collect life insurance. Id. at 223. The Court did not invoke the doctrine of

chances by name, but rejected the defendant’s argument that the death of his first

wife was “wholly disconnected from the crime charged” and upheld the rule of

evidence as applied. See id. at 226–27.

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404(b) evidence. There, defendant Commanche faced criminal assault charges

after injuring two unarmed opponents with a box cutter in a fight. Commanche,

577 F.3d at 1263. Commanche claimed he acted in self defense, and the

government sought to introduce evidence of his two prior convictions for

aggravated battery for altercations in which he brandished sharp cutting

instruments. See id. at 1263–65. We concluded the evidence was irrelevant

because “[t]he only disputed issue at trial was whether Commanche acted in self

defense.” Id. at 1265. The fact “[t]hat Commanche ha[d] twice been convicted of

battering people in the past . . . ha[d] no direct bearing on whether he acted in self

defense in this particular instance.” Id. at 1268. As we explained, Commanche

was not a case “in which intent is proven circumstantially based on repeated

substantially similar acts” because the details of his prior convictions

“demonstrate nothing about his intent; they simply show that he is violent.” Id. at

1269. Notably, “[t]here [wa]s no indication in the record that Commanche

claimed self defense on the other two occasions.” Id.

Unlike the defendant in Commanche, Henthorn has repeatedly asserted the

same defense—i.e., that he and his wives have been victims of multiple tragic

accidents. The prior incidents admitted here have many more marks of similarity,

especially those pointing to motive, intent, and planning. Our case is thus more

akin to a hypothetical version of Commanche in which the defendant was

involved in several fights and always claimed self-defense. At some point, the

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court may reasonably begin to question whether the defendant actually acted in

self-defense and whether his use of force was justified.9

Although the evidence may allow the jury to draw negative inferences

about Henthorn’s character, such inferences are not required before a jury may

9

 This is not a novel proposition. For example, in State v. Roth, 881 P.2d

268 (Wash. App. 1994), the court upheld the trial court’s decision to admit

evidence of the mysterious death of defendant Roth’s second wife when Roth was

on trial for his fourth wife’s death. See id. at 271. Roth was not charged after his

second wife fell from a cliff while the couple was hiking, and he collected

significant life insurance proceeds. Id. Roth was charged, however, after his

fourth wife drowned during an outing on an inflatable raft. Id. The court

presiding over Roth’s trial for murdering his fourth wife admitted evidence of the

second wife’s death to help prove Roth’s intent, including “proof of scheme or

plan, proof of motive, proof of distinctive modus operandi, to rebut a claim of

accident, and under the doctrine of chances.” Id. at 272. The trial court found

the evidence of the second wife’s death “highly relevant” and the appellate court

further emphasized that the evidence was particularly probative because Roth’s

defense at trial was that his fourth wife’s injuries occurred by happenstance or

misfortune (i.e., that her death was an accident). See id. 273–75. As the court

explained,

[A] material issue of accident arises where the defense is denial and the

defendant affirmatively asserts that the victim’s injuries occurred by

happenstance or misfortune. . . . It is undisputed that Roth’s defense

was that [his fourth wife’s] drowning was accidental—i.e., that no

crime occurred. Clearly, then, evidence of a prior incident in which

Roth married, insured, and murdered a woman would be highly relevant

to a crucial aspect of the State’s case: the need to rebut Roth’s claim of

accident and to establish an intentional killing. Thus, as the trial court

concluded, the evidence was highly relevant as to a material assertion

of the defendant.

Id. at 275. “[T]he marked similarities between the victims, the physical

circumstances of the crimes, and the relatively complex nature of the crimes”

further supported “a commonsense inference that the deaths of Roth’s spouses

were not mere fortuities.” Id. at 276.

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find that the prior incidents are relevant for a proper purpose—i.e., that they bear

on Henthorn’s intent, motive, plan, or lack of accident. The inference here, as in

Moran, is specific and rests on a logic of improbability recognizing that a prior

act involving similar circumstances decreases the likelihood that Henthorn lacked

the specific intent in committing the charged offense.

c. Preliminary Rule 104(b) finding

“[I]n the Rule 404(b) context, similar act evidence is relevant only if the

jury can reasonably conclude that the act occurred and that the defendant was the

actor.” Dowling v. United States, 493 U.S. 342, 346 (1990) (citing Huddleston,

458 U.S. at 689). This requirement stems from Federal Rule of Evidence 104(b),

which, “[w]hen the relevance of evidence depends on whether a fact exists,”

requires proof “sufficient to support a finding that the fact does exist.” Fed. R.

Evid. 104(b); see also Huddleston, 458 U.S. at 689–91.

In its order admitting the challenged evidence, the district court readily

acknowledged the prior incidents did “not present a typical prior-bad-act

scenario.” See R., Vol. I, pt. 1, at 224. “Usually, the prior act is clearly a bad

act,” but Henthorn insisted each incident was merely an accident. Id. (emphasis

removed). And if the incidents were all accidents, the evidence would be

irrelevant. As a prerequisite for admitting the evidence, then, the district court

made two Rule 104(b) findings.

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First, as to Lynn’s death, the district court found there was sufficient

evidence “for a jury to reasonably find the conditional fact—that Mr. Henthorn

orchestrated the murder of Lynn Henthorn—by a preponderance of the evidence.” 

Id. at 225. In reaching this conclusion, the district court credited evidence from

the government “expos[ing] a number of discrepancies in Mr. Henthorn’s various

accounts of the events leading to the death of Lynn Henthorn,” including: “[1]

which of the couple was changing the tire; [2] whether one or two jacks were used

to prop up the car initially; [3] whether the couple was returning from dinner or

heading to dinner when the accident occurred; and [4] at what time the couple left

their house that day.” Id. Circumstantial evidence further supported the

government’s theory, including:

[1] the fact that there was a shoe print on the wheel well of the tire

being changed suggesting that the car may have been kicked or pushed

off of the jack; [2] that the tire being replaced was not flat but only had

low pressure, and that the spare tire had similarly low pressure; [3] that

no lubricant was found in an inventory of the car to support Mr.

Henthorn’s allegation that he attempted to lubricate the proper jack so

that he could use it; [4] that a passerby had stopped and offered to help

change the tire, but that Mr. Henthorn declined his offer; [5] that the

same passerby offered to shine his headlights on the car, which Mr.

Henthorn also declined in spite of [its] being dark with no lights on the

road and his only having a mini-flashlight; [6] that the incident

occurred without any witnesses and in a remote location that delayed

emergency responders; and [7] that in attempts to physically recreate

the incident as told by Mr. Henthorn investigators have been

unsuccessful.

Id. In addition, the government proffered evidence of Henthorn’s inexplicable

interactions with a second group of passersby after the car fell on Lynn, including

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that “Henthorn attempted to prevent them from performing CPR on Lynn” and,

because Henthorn “refused to warm Lynn with his coat in spite of the nearfreezing temperatures,” “the passersby instead placed their coats on her.” Id. at

226. And the district court recognized testimony suggesting that in the aftermath

of the incident the cremator found Henthorn’s “insistence that Lynn be

immediately cremated” to raise suspicion, and a deputy coroner investigator

working on the case wanted to develop additional evidence but was not permitted

to do so. See id. It was also discovered that, although Henthorn mentioned only

one life insurance policy when he was questioned by officials, there were actually

three policies in Lynn’s name. See id. Combined, the district court thus found

there was “sufficient evidence to support a reasonable finding by a jury that it is

more likely than not that Lynn Henthorn’s death was not an accident but instead a

murder.” Id.

Second, as to Toni’s previous injury at the cabin near Grand Lake, the

district court found “a jury could reasonably find by a preponderance of the

evidence that the deck incident was not an accident, but rather a deliberate

attempt to bring about his wife’s death.” Id. at 236. In reaching this conclusion,

the district court determined the deck incident was “analytically similar” to the

tire-changing incident. See id. at 235. As the district court explained,

The circumstances of the accident were unusual. The Henthorns were

ostensibly doing work outside their cabin late at night. Mr. Henthorn

allegedly tossed or dropped a board over the edge of the deck, and it

-24-
struck his wife, who was picking up broken glass on the ground below,

on the back of her neck. No one else was present. Toni sustained

injuries serious enough to be taken to the local hospital and then

transported to a trauma center in Denver, although the injuries turned

out to be less serious than the initial diagnosis. Mr. Henthorn allegedly

told inconsistent stories about what happened. He was the beneficiary

of substantial insurance on Toni’s life.

Id. The district court recognized this was a close call, and that while “[b]eing hit

by a board dropped from ten feet may well cause serious injury, depending upon

the size of the board and where the victim is hit,” it would be “markedly less

likely” to result in death than being pinned under a car or pushed off a cliff, and

may be “an odd way to attempt it.” Id.10 Considering “all the evidence

presented,” however, the district court concluded that “a jury could reasonably

find that the deck incident was a deliberate attempt on Mr. Henthorn’s part to kill

his wife, rather than an accident.” Id.

Henthorn has not challenged either of these Rule 104(b) findings on appeal. 

And the jurors were repeatedly instructed to ignore the evidence of the prior

incidents if they decided they were accidents.

* * *

We are satisfied that the second Huddleston factor is met.

10 We generally agree with the district court that admitting evidence of the

Grand Lake deck incident was a “closer call” than admitting evidence of the tirechanging incident. R., Vol. I, pt. 1, at 235. Even if the district court’s decision to

admit evidence of the Grand Lake deck incident was error, however, we would

find that any error was harmless in light of the tire-changing incident and other

incriminating evidence presented at trial. 

-25-
3. Factor Three: Probative Value Versus Unfair Prejudice

The third Huddleston factor requires the evidence’s probative value not be

substantially outweighed by its potential for unfair prejudice. The corresponding

Federal Rule of Evidence provides that a court “may exclude evidence if its

probative value is substantially outweighed by a danger of one or more of the

following: unfair prejudice, confusing the issues, misleading the jury, undue

delay, wasting time, or needlessly presenting cumulative evidence.” Fed. R. Evid.

403. The exclusion of evidence under Rule 403 “is an extraordinary remedy and

should be used sparingly.” Brooks, 736 F.3d at 940 (quoting Tan, 254 F.3d at

1211). 

“Evidence is unfairly prejudicial if it makes a conviction more likely

because it provokes an emotional response in the jury or otherwise tends to affect

adversely the jury’s attitude toward the defendant wholly apart from its judgment

as to his guilt or innocence of the crime charged.” United States v. MacKay, 715

F.3d 807, 840 (10th Cir. 2013) (citation omitted) (emphasis added). “In engaging

in the requisite balancing,” courts “give the evidence its maximum reasonable

probative force and its minimum reasonable prejudicial value.” United States v.

Cerno, 529 F.3d 926, 935 (10th Cir. 2008). And “it is not enough that the risk of

unfair prejudice be greater than the probative value of the evidence; the danger of

that prejudice must substantially outweigh the evidence’s probative value.” Id.

“The trial court has broad discretion to determine whether prejudice inherent in

-26-
otherwise relevant evidence outweighs its probative value” and, for this court to

overturn a district court’s exercise of this discretion on appeal, we must be able to

say the court made an “obvious” or “substantial” error. See United States v.

Magallanez, 408 F.3d 672, 678–79 (10th Cir. 2005) (citation omitted).

Here, in admitting the challenged evidence the district court reasoned that

“[a]lthough this evidence might provoke an emotional response, it would not do

so ‘wholly apart’ from its relevance to rebutting the defense of accident or to

showing plan or intent.” R., Vol. I, pt. 1, at 231. The district court found that

any prejudice resulting from the admission of the evidence was “therefore not

‘unfair’” and, in any event, would not substantially outweigh the evidence’s

probative value. See id. at 231; id. at 237 (“As with the [tire-changing]

incident, . . . the probative value of [the Grand Lake deck incident] is not

substantially outweighed by the danger of unfair prejudice. If it were viewed by

the jury as an accident, the deck incident would not reasonably provoke an

emotional response adverse to Mr. Henthorn. If viewed by the jury as not having

been an accident, then the deck incident presumably would adversely affect the

jury’s attitude toward Mr. Henthorn, but . . . not [ ] wholly apart from the jury’s

judgment as to his guilt or innocence of the crime charged.”).

Assuming maximum reasonable probative force and minimum reasonable

prejudicial value, Cerno, 529 F.3d at 935, we cannot say the district court abused

its discretion in completing its Rule 403 balancing inquiry. While evidence of the

-27-
prior incidents was undoubtedly prejudicial in the broad sense, it was also highly

probative of lack of accident and Henthorn’s specific intent. Even if reasonable

jurists may have weighed the Rule 403 factors differently and reached a different

conclusion about the evidence’s admissibility, we cannot say the district court

made an “obvious” or “substantial” error. 

Thus, the third Huddleston factor is satisfied.

4. Factor Four: Limiting Instruction

The fourth and final Huddleston factor requires the district court, upon

request, to instruct the jury to consider the evidence only for the purpose for

which it was admitted. The corresponding Federal Rule of Evidence provides that

“[i]f a court admits evidence that is admissible . . . for a purpose—but not . . . for

another purpose—the court, on timely request, must restrict the evidence to its

proper scope and instruct the jury accordingly.” Fed. R. Evid. 105. For example,

“[a] limiting instruction cautions the jury that the Rule 404(b) evidence should be

considered only for the purposes for which it was admitted and not as evidence of

the defendant’s character or propensity to commit an offense.” Davis, 636 F.3d at

1298.

Here, the district court gave limiting instructions both when the evidence of

the tire-changing and Grand Lake deck incidents was first admitted at trial and

again in the closing jury instructions. When the jury first heard the evidence at

trial, the district court explained that the jurors could only consider the evidence

-28-
for the limited purposes of: (1) rebutting the defense that Toni’s death was an

accident; and (2) establishing planning and intent by Henthorn regarding Toni’s

death. See R., Vol. VII, at 937–38 (Grand Lake deck incident); id. at 1063 (tirechanging incident). The instructions also emphasized that Henthorn’s

commission of the acts involved in the prior incidents did not mean that he

necessarily committed the act charged in the case, and that, if the jury decided

Henthorn did not commit the acts involved in the prior incidents they were “not to

consider the evidence about [the prior incidents] for any purpose.” See id. at 938

(Grand Lake deck incident); id. at 1063–64 (tire-changing incident). When a

juror asked the court to repeat the cautionary instruction, it did. See id. at 939. 

After taking into account both parties’ proposed 404(b) instructions, the

court’s written instructions at the close of trial again carefully cabined the jury’s

use of the prior acts evidence. The final instructions read as follows:

During the trial you heard evidence about [the tire-changing and

Grand Lake deck incidents]. When you heard that evidence I gave you

an instruction about it. I am now repeating that instruction.

You may consider the evidence about this incident only for the

following limited purposes: (1) rebutting the defense that Toni

Henthorn’s death was an accident; and (2) establishing planning and

intent by the defendant regarding Toni Henthorn’s death.

The fact the defendant may have previously committed [the tirechanging or Grand Lake deck acts] does not mean that he necessarily

committed the act charged in this case.

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If after your consideration of all the evidence, you decide [the

tire-changing or Grand Lake deck incident] was an accident, then you

are not to consider the evidence about that act for any purpose. 

R., Vol. I, pt. 2, at 94–95. These instructions mirrored the defense’s proposed

404(b) instructions with only minor modifications.11

We are satisfied these instructions adequately advised the jury of its

obligations under Rule 404(b). And, “absent a showing to the contrary, we

‘presume jurors will conscientiously follow the trial court’s instructions.’” 

Brooks, 736 F.3d at 941 (citation omitted).

The district court’s repeated explanations readily satisfy the fourth

Huddleston factor.

III. Conclusion

All four Huddleston factors are met—the government offered the evidence

of the two prior incidents for a proper purpose under Rule 404(b), the evidence

was relevant under Rule 401, the probative value of the evidence was not

substantially outweighed by its potential for unfair prejudice under Rule 403, and

the district court repeatedly instructed the jury pursuant to Rule 105 to consider

the evidence only for the purpose for which it was admitted. Accordingly, we

11 In particular, the court’s final instructions substituted “the defendant”

for “Mr. Henthorn” twice and, in the final paragraph, used the phrase “If after

your consideration of all the evidence, you decide the [tire-changing / Grand Lake

deck] act was an accident” rather than “If you decide that Mr. Henthorn did not

commit the [tire-changing / Grand Lake deck] act.” Compare R., Vol. I, pt. 1, at

267–70, with R., Vol. I, pt. 2, at 94–95. 

-30-
hold the district court did not abuse its discretion in admitting the challenged

evidence and thus AFFIRM Henthorn’s conviction.

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