FOR PUBLICATION

UNITED STATES COURT OF APPEALS

FOR THE NINTH CIRCUIT

UNITED STATES OF AMERICA,  No. 10-50575

Plaintiff-Appellee, D.C. No.

v.  3:09-CR-03175-

JAH-1 ENRIQUE ACOSTA-SIERRA,

Defendant-Appellant. OPINION 

Appeal from the United States District Court

for the Southern District of California

John A. Houston, District Judge, Presiding

Argued and Submitted

December 7, 2011—Pasadena, California

Filed August 15, 2012

Before: Dorothy W. Nelson, Ronald M. Gould, and

Sandra S. Ikuta, Circuit Judges.

Opinion by Judge Nelson

9271
COUNSEL

Jason I. Ser (argued), Federal Defenders of San Diego, Inc.,

San Diego, California, for the defendant-appellant.

9274 UNITED STATES v. ACOSTA-SIERRA
James P. Melendres, Assistant U.S. Attorney (argued), Bruce

R. Castetter, Assistant U.S. Attorney, Chief, Appellate Section, Criminal Division, Laura E. Duffy, United States Attorney, Office of the United States Attorney, San Diego,

California, for the plaintiff-appellee. 

OPINION

NELSON, Senior Circuit Judge:

Defendant-Appellant Enrique Acosta-Sierra (“AcostaSierra”), a 57-year-old native and citizen of Mexico who has

been diagnosed with paranoid schizophrenia, appeals from his

conviction, following a bench trial, of two counts of assault

on a federal officer in violation of 18 U.S.C. § 111. 

Acosta-Sierra raises four claims on appeal: (1) that the district court’s findings of fact and conclusions of law pursuant

to Rule 23(c) of the Federal Rules of Criminal Procedure were

insufficient to find Acosta-Sierra guilty of assault on a federal

officer with a dangerous and deadly weapon in violation of 18

U.S.C. §§ 111(a)(1) & (b); (2) that the district court erred in

denying Acosta-Sierra’s motion for a judgment of acquittal

pursuant to Rule 29 of the Federal Rules of Criminal Procedure; (3) that the district court erred when it concluded that

18 U.S.C. § 111 did not require the government to prove specific intent, and thereby precluded Acosta-Sierra from presenting a diminished capacity defense; and (4) that the district

court erred when it precluded mental health evidence in support of Acosta-Sierra’s self-defense claim. 

We have jurisdiction pursuant to 18 U.S.C. § 1291. We

reverse in part, affirm in part, and remand to the district court

for further proceedings consistent with this opinion.

I. BACKGROUND

On June 18, 2009, Acosta-Sierra walked across the United

States border from Mexico at the San Ysidro, California, Port

UNITED STATES v. ACOSTA-SIERRA 9275
of Entry. While in a lane designated for vehicles, AcostaSierra threw a baseball-size piece of jagged concrete in the

direction of United States Customs and Border Protection

Officer Abram Lopez, who was walking approximately seven

to eight feet in front of a closed, unmanned primary inspection booth. 

The rock did not strike Officer Lopez, though it came

within two feet of hitting his head. Officer Lopez did not see

Acosta-Sierra throw the rock or observe it travel through the

air. In fact, Officer Lopez only became aware of the rock

when he heard it hit the metal gate behind him, and bounce

off of the gate into the inspection booth. He did not fear

immediate bodily harm at the time he heard the rock hit the

gate. Instead, he felt stunned and confused. 

It was only after Officer Lopez heard the rock hit the gate,

repositioned himself to see from where the rock originated,

saw Acosta-Sierra walking in his general direction from six to

seven car lengths away, and observed his fellow officers moving to arrest Acosta-Sierra that Officer Lopez started to feel

“a little scared of the situation that was going on.” He did not

see Acosta-Sierra holding any other rocks at that time. 

Based on these events, the government charged AcostaSierra with assault on a federal officer in violation of 18

U.S.C. §§ 111(a)(1) and (b) (“Count 2”).1 The government

alleged that Acosta-Sierra “did knowingly and intentionally

and forcibly assault . . . United States Customs and Border

Protection Officer A. Lopez, in that defendant did throw baseball size rocks at Agent Lopez while he was engaged in the

performance of his official duties, and in committing such

offense, did use dangerous and deadly weapons, to wit,

rocks.” 

1The government also charged Acosta-Sierra with illegal reentry after

deportation in violation of 8 U.S.C. § 1326 (“Count 1”), though the district

court subsequently dismissed this charge. 

9276 UNITED STATES v. ACOSTA-SIERRA
On December 7, 2009, while awaiting trial, Acosta-Sierra

was transported to an individual holding cell at the courthouse. District Security Officer Mark Burrola approached

Acosta-Sierra in the holding cell to handcuff him and to transport him to the courtroom. Acosta-Sierra walked backwards

toward the cell door with his hands behind his back so that

Officer Burrola could handcuff him, but when Officer Burrola

opened the cell door, Acosta-Sierra turned around and

punched Officer Burrola on the left side of his head. Although

Officer Burrola did not require medical attention, his “ear felt

hot.” 

In light of this incident, the government filed a Second

Superseding Indictment which added Count 3 and charged

Acosta-Sierra with assault on a federal officer in violation of

18 U.S.C. § 111(a)(1) for “punch[ing] Officer Burrola, while

Officer Burrola was engaged in the performance of his official duties.” 

Prior to trial, the district court denied Acosta-Sierra’s in

limine motions seeking to introduce expert testimony that

Acosta-Sierra suffered from paranoid schizophrenia and delusions of being subject to persecution and torture by governmental authorities. The district court held that this evidence

was not admissible to prove a diminished capacity defense

because Section 111 is a general intent crime. The district

court also held that this evidence was inadmissible to present

a theory of self-defense because “there was no use of force,

let alone any excessive force, from which one might reasonably suggest that a cognizable theory of self-defense would

lie.” Acosta-Sierra waived his right to a jury trial due to these

rulings. 

Following a two-day bench trial, the district court found

Acosta-Sierra guilty on both counts of assaulting a federal

officer and denied his Rule 29 motion for a judgment of

acquittal. In finding Acosta-Sierra guilty of Count 2, the court

found beyond a reasonable doubt (1) that Acosta-Sierra intenUNITED STATES v. ACOSTA-SIERRA 9277
tionally used force in assaulting Officer Lopez, (2) that Officer Lopez was engaged in his official duties at the time of the

assault, and (3) that the baseball-size rock that Acosta-Sierra

threw constituted a dangerous or deadly weapon. As for the

first element, the district court found that “there was a display

of force” that “reasonably caused a person to fear immediate

bodily harm.” The district court also concluded that the government did not need to prove that Acosta-Sierra “intentionally used force against Officer Lopez or someone else”

because “this is a general intent crime, not a specific intent

crime.” 

In finding Acosta-Sierra guilty of Count 3, the court found

beyond a reasonable doubt that Acosta-Sierra intentionally

used force in assaulting Officer Burrola based on the “aggression” revealed by “the power of th[e] first punch” as well as

the “way [Acosta-Sierra] went after [Officer Burrola] to try to

hit him the second time.” The court further found that there

was no evidence that Officer Burrola applied any force, let

alone excessive force, such that a reasonable person would

consider self-defense necessary. In addition, the court found

“more than sufficient evidence was presented for the Court to

find beyond a reasonable doubt that Officer Burrola was performing in the execution of his official function at the time of

the assault.” 

In November 2010, the district court sentenced AcostaSierra to 60 months in prison on Count 2 and 36 months on

Count 3, with those terms to run concurrently, as well as three

years of supervised release. Acosta-Sierra then filed a timely

appeal.

II. STANDARD OF REVIEW 

We review mixed questions of law and fact de novo. See

United States v. Juvenile (RRA-A), 229 F.3d 737, 742 (9th

Cir. 2000). We also review de novo a district court’s denial

of a motion for a judgment of acquittal based on insufficient

9278 UNITED STATES v. ACOSTA-SIERRA
evidence. United States v. Chapman, 528 F.3d 1215, 1218

(9th Cir. 2008). In so doing, we must determine whether,

“after viewing the evidence in the light most favorable to the

prosecution, any rational trier of fact could have found the

essential elements of the crime beyond a reasonable doubt.”

Jackson v. Virginia, 443 U.S. 307, 319 (1979). “[W]hen faced

with a record of historical facts that supports conflicting inferences . . . [we] must presume—even if it does not affirmatively appear in the record—that the trier of fact resolved any

such conflicts in favor of the prosecution, and must defer to

that resolution.” United States v. Nevils, 598 F.3d 1158, 1164

(9th Cir. 2010) (en banc) (internal quotation marks and citation omitted).

Whether diminished capacity is a defense to a charged

offense is reviewed de novo. United States v. Vela, 624 F.3d

1148, 1154 (9th Cir. 2010). We review for abuse of discretion

a district court’s decision to admit or exclude scientific evidence. United States v. Finley, 301 F.3d 1000, 1007 (9th Cir.

2002).

III. ANALYSIS

A. Count 2

[1] Section 111 of 18 U.S.C. prohibits forcible assault on

a federal officer “while engaged in or on account of the performance of official duties.” 18 U.S.C. § 111(a)(1). Because

Section 111 does not define assault, we have adopted the

common law definition of assault as either (1) “a willful

attempt to inflict injury upon the person of another,” or (2) “a

threat to inflict injury upon the person of another which, when

coupled with an apparent present ability, causes a reasonable

apprehension of immediate bodily harm.” Chapman, 528 F.3d

at 1219-20 (quoting United States v. Dupree, 544 F.2d 1050,

1051 (9th Cir. 1976)); see generally United States v. Turley,

352 U.S. 407, 411 (1957) (“[W]here a federal criminal statute

uses a common-law term of established meaning without othUNITED STATES v. ACOSTA-SIERRA 9279
erwise defining it, the general practice is to give that term its

common-law meaning.”).

The first type of common law assault is an attempt to commit a battery. United States v. Bell, 505 F.2d 539, 540 (7th

Cir. 1974). For this type of assault, there need not be physical

contact with the intended victim, see Chapman, 528 F.3d at

1219 (explaining that “someone who threw a punch and

missed” would be guilty of assault under Section 111), or reasonable apprehension on the part of the victim, see United

States v. Lewellyn, 481 F.3d 695, 697 (9th Cir. 2007)

(explaining that “a showing of fear on the part of the victim”

is not required under the attempted battery theory of assault).

The second type of criminal assault, sometimes called an

“intent-to-frighten,”

2

 derives from the law of torts, Bell, 505

F.2d at 540, and recognizes the importance of protecting individuals from the mental disturbance of being put in reasonable apprehension of bodily harm, Price v. United States, 156

F. 950, 953 (9th Cir. 1907) (citing Beach v. Hancock, 27 N.H.

223 (1853)). For this latter type of assault, one does not necessarily need to be put in actual danger. Id. at 952-53. Even

if one is only put in reasonable apprehension of imminent

harm, the “suffering is the same in the one case as in the

other, and the breach of the public peace is the same.” Id.

(internal quotation marks and citation omitted).

Although the two types of common law assault involve distinct elements, the difference between them often goes unno2

See Wayne R. LaFave, 2 Substantive Criminal Law § 16.3(a), at 565,

568 n.28 (2d ed. 2003) (characterizing the second type of assault as “intentional scaring” or “intent-to-frighten,” though noting that the words

“scare” and “frighten” are sometimes used as shorthand “for the more

cumbersome but more accurate expression ‘causing reasonable apprehension of immediate bodily harm.’ ”) (quoting W. Prosser & W. Keeton,

Torts § 10, at 44 (5th ed. 1984)); see also United States v. Lee, 199 F.3d

16, 19 (1st Cir. 1999) (referring to this second type of assault as “assault

by menace”). 

9280 UNITED STATES v. ACOSTA-SIERRA
ticed because a violation of one type is usually a violation of

the other type as well. As a fitting example: 

If, with the intention of hitting X, D wrongfully

threw a stone that X barely managed to dodge, then

D would have been guilty of a criminal assault

because he had attempted to commit a battery, and

he would also have been liable in a civil action of

trespass for assault because he had wrongfully

placed X in apprehension of physical harm. 

R. Perkins & R. Boyce, Criminal Law § 2, at 159 (3d ed.

1987). This example highlights the important nuances

between the two prongs of common law assault. The question

here is whether Acosta-Sierra is guilty of assault if the rock

he threw narrowly missed Officer Lopez, and Officer Lopez

did not see the rock or feel afraid until immediately after it

landed.

Although Acosta-Sierra’s rock-throwing seems to be a

straightforward example of attempted battery, the district

court analyzed his conduct under only the “reasonable apprehension of harm” prong of common law assault. In concluding that the attempted battery prong did not apply to this case,

the district court was apparently misled by the Ninth Circuit

Pattern Jury Instructions in effect at the time of AcostaSierra’s trial, which stated that an assault occurs only “when

one person intentionally [strikes] [wounds] another, or when

one person intentionally makes a display of force which reasonably causes a person to fear immediate bodily harm.” 9th

Cir. Model Crim. Jury Instr. 8.2 (2008); but see Chapman,

528 F.3d at 1219 (holding that assault, for purposes of Section

111, incorporates the common law definition of assault).3

3The instructions now correctly include attempted battery as a basis for

forcible assault by stating that “[t]here is a forcible assault when one person intentionally strikes another, or willfully attempts to inflict injury on

another, or makes a threat coupled with an apparent ability to inflict injury

UNITED STATES v. ACOSTA-SIERRA 9281
In concluding that Acosta-Sierra’s rock-throwing constituted assault under the “reasonable apprehension of harm”

prong, the district court made the following factual findings:

Officer Lopez, while crossing through lane 12 in

front of its closed gate, heard a very loud bang. At

that moment, he shrugged and managed with his

peripheral vision to see an object bounce off the top

of the closed gate into one of the unmanned booths

and then to the ground. He noticed that the object

was a jagged-edged rock.

At the time he heard the object hit the gate, he was

stunned. He was still confused as to what was going

on as he redirected his attention to see where the

object was coming from. He then saw the defendant

advancing towards him through the traffic lanes, and

his confusion turned to feeling threatened and scared

of the situation that was going on. He stated he was

not too sure what would happen next. Officer Lopez

considered the matter to be a serious event.

On cross-examination, Lopez testified that he was

not worried about being hurt because he was not

aware he was being attacked. He did not necessarily

fear any immediate bodily harm, but was confused at

the time he heard the rock. He testified that he

on another which causes a reasonable apprehension of immediate bodily

harm.” 9th Cir. Model Crim. Jury Instr. 8.4 (2010) (emphasis added). 

The current pattern jury instructions do not, however, specify what level

of criminal intent the government must prove when an individual “makes

a threat coupled with an apparent ability to inflict injury on another which

causes a reasonable apprehension of immediate bodily harm.” As we

explain further in Part III.A.2, the requisite criminal intent under this theory of assault is the intent to assault. See United States v. Juvenile Female,

566 F.3d 943, 947 (9th Cir. 2009); United States v. Kartman, 417 F.2d

893, 895 (9th Cir. 1969).

9282 UNITED STATES v. ACOSTA-SIERRA
became scared afterwards, after turning his attention

towards the defendant.

Based on these findings, the court concluded, first, that the

government did not need to prove that Officer Lopez subjectively feared immediate bodily harm due to the rock throwing

because Section 111 requires a different level of proof than

that of Section 113, the general federal assault statute. The

district court then determined that “the events of hearing the

rock hit the gate behind [Officer Lopez] . . . watching it fall

behind him and turning to see the defendant advancing on him

created a display of force reasonably causing a person to fear

immediate bodily harm.” In the alternative, the district court

determined that these events actually “caused the victim to

sense the fear and harm.” By emphasizing that “the events

occurred within . . . fluid and seamless seconds,” the court

rejected Acosta-Sierra’s claim that Officer Lopez’s “feelings

of being threatened and scared” occurred after the rock hit the

gate. The court ultimately decided that the close proximity of

events sufficed “to create th[e] fear that satisfies the element

of 111.” 

We conclude that the district court erred in its application

of the “reasonable apprehension of harm” prong of common

law assault. However, because the evidence would have been

sufficient to convict Acosta-Sierra of attempted battery if the

district court had not relied on the erroneous model jury

instruction then in effect, we remand for retrial under the

proper standard. See United States v. Cote, 51 F.3d 178,

182-83 (9th Cir. 1995) (holding that the Double Jeopardy

Clause does not bar retrial when a conviction is reversed for

trial error such as an incorrect jury instruction, but the evidence is not insufficient to sustain a conviction under the

proper standard).

UNITED STATES v. ACOSTA-SIERRA 9283
1. Reasonable Apprehension of Immediate

Bodily Harm

[2] We first consider whether Acosta-Sierra’s rock throwing constituted assault because it was “a threat to inflict injury

upon the person of another which, when coupled with an

apparent present ability, causes a reasonable apprehension of

immediate bodily harm.” Chapman, 528 F.3d at 1219-20

(quoting Dupree, 544 F.2d at 1051). We agree with the district court that, for purposes of Section 111, a victim’s apprehension of immediate bodily injury must be determined by an

objective standard of reasonableness. Therefore, to prove

criminal assault under the “reasonable apprehension of harm”

prong, the evidence must permit an inference that a reasonable person “standing in the official’s shoes,” that is, observing what the official observed, would have apprehended

imminent bodily injury. United States v. Walker, 835 F.2d

983, 987 (2d Cir. 1987); see also id. at 989 (describing the

reasonable apprehension requirement as an “objective standard”).4

Acosta-Sierra argues that, to be convicted of assault, the

government must prove beyond a reasonable doubt that Officer Lopez also subjectively feared immediate bodily harm. In

so doing, Acosta-Sierra relies on United States v. Skeet, for

the proposition that “fear on the part of the victim” is a necessary element of assault. 665 F.2d 983, 986, 987 (9th Cir.

1982). We disagree. Skeet involved an assault conviction

under 18 U.S.C. § 113, the general federal assault statute, and,

therefore, the court did not consider the enhanced protections

4Contrary to the government’s argument, we have not previously

adopted an objective standard of reasonable apprehension of harm.

Although, in United States v. Jim, we stated that, if Section 111 were a

general intent crime, the “only issue would be whether a reasonable man

would find that the defendant’s actions should have put a federal officer

in apprehension of bodily harm,” 865 F.2d 211, 213 (9th Cir. 1989), this

was mere dicta. Our holding in Jim was limited to resolving whether Section 111 is a general or specific intent crime. Id. at 215. 

9284 UNITED STATES v. ACOSTA-SIERRA
we have afforded federal officials under Section 111. See Jim,

865 F.2d at 213-15 (contrasting our construction of federal

forcible assault pursuant to Section 111 with the assault prohibited under Section 113 in light of Congress’s intent, in

passing Section 111, “ ‘to protect both federal officers and

federal functions’ ” (quoting United States v. Feola, 420 U.S.

671, 679 (1975))). Moreover, even when construing assault in

contexts outside of Section 111, we have required that fear of

personal harm be reasonable. See Price, 156 F. at 953 (“We

have a right to live in society without being put in fear of personal harm. But it must be a reasonable fear of which we

complain.”) (internal quotation marks and citation omitted)

(emphasis added); see also Restatement (Second) of Torts

§ 24 (1965) (explaining that “[t]he apprehension which is sufficient to make the actor liable [for assault] may have no relation to fear” and that “the heavyweight champion pugilist of

the world” may be put in the requisite apprehension by “a

scrawny individual who is intoxicated” even if the former is

“not at all afraid of the latter”).

An objective standard strikes a balance between protecting

federal officials and their functions while also giving effect to

the common law theories underlying criminal assault. An

objective standard guards against liability for subjective but

unreasonable apprehension of imminent bodily harm, and, at

the same time, allows prosecution for assault when a reasonable person in the federal official’s shoes would fear immediate injury, but the official happens to be particularly stoic or

confident in his ability to resist an attack. 

In this case, however, the district court found reasonable

apprehension based on information beyond what someone in

Officer Lopez’s shoes would know, explaining that it was

“not impressed with the position that the victim needs to see

the rock hurling in his direction or observ[e] a near miss and

be[ ] fearful instantaneously.” In so doing, the district court

applied an overly-broad construction of the reasonableness

UNITED STATES v. ACOSTA-SIERRA 9285
standard and conflated the two concepts of common law

assault. 

As noted previously, when an individual is charged with

assault as an attempted battery, the victim’s apprehension of

imminent harm is inconsequential. See, e.g., Skeet, 665 F.2d

at 987 (noting that fear on the part of the victim is not an

essential element of the assault charge which involved battery

based on a gunshot wound); Bell, 505 F.2d at 541 (noting that

when “an attempted battery is an assault, it is irrelevant that

the victim is incapable of forming a reasonable apprehension”); LaFave, 2 Substantive Criminal Law § 16.3(a), at 567

(stating that an attempted battery “may be committed though

the victim is unaware of his danger, as where A throws a rock

at, but misses, B who is asleep, or where A shoots from the

south at B who is facing north”) (emphasis added).

[3] In contrast, for a criminal assault based on causing the

apprehension of imminent bodily injury, the common law

requires awareness of the threat. See generally LaFave, 2

Substantive Criminal Law § 16.3(b), at 569 (“It is not enough,

of course, to intend to scare the other without succeeding; if

the other fails to notice the threatened battery, the threatener,

not having succeeded in his plan, cannot be held guilty of

assault.”); Prosser & Keeton, Torts § 10 at 44 (“Since the

interest involved is the mental one of apprehension of contact,

it should follow that the plaintiff must be aware of the threat

of contact, and that it is not an assault to aim a gun at one who

is unaware of it.”); Restatement (Second) of Torts § 26, Comment a (1965) (“The gist of the liability is the other’s knowledge that the actor is attempting to commit a battery upon

him.”); see, e.g., State v. Barry, 124 P. 775, 777 (Mont. 1912)

(finding no assault where the defendant leveled a rifle at a

prosecutor who did not see the defendant until after the defendant had been rendered harmless, because “it would seem

impossible for any reasonable man in [the prosecutor’s] position to affirm that he was then in fear for his safety”). 

9286 UNITED STATES v. ACOSTA-SIERRA
[4] Thus, contrary to the district court’s conclusion, an

objective reasonable person standard does not consider the

reasonable person who is aware of all the relevant circumstances. Rather, it considers the reasonable person who

observes what the official observes. The paradigmatic example of a defendant brandishing an unloaded gun illustrates

why the district court’s standard does not best protect federal

officials in the performance of their functions. We have held

that “if within shooting distance one menacingly points at

another with a gun, apparently loaded, not loaded in fact, he

commits an assault the same as if it were loaded.” Price, 156

F. at 953 (internal quotation marks and citation omitted). At

the time the individual brandishes the weapon, it is reasonable

for a person in the victim’s shoes to apprehend immediate

bodily harm. Id. We do not presume knowledge, however,

beyond what one can observe when standing in the victim’s

shoes. Officers must be empowered to respond to apparent

threats of violence without first being required to learn or confirm all the relevant facts in an altercation, such as whether a

gun is in fact unloaded. To apply too high a standard of apprehension may, in certain circumstances, undermine protections

for federal officials. 

[5] The district court erred in concluding that AcostaSierra caused a reasonable apprehension of immediate bodily

harm under an objective standard of reasonableness because

the district court did not limit its consideration to the facts

known to Officer Lopez. Officer Lopez did not see AcostaSierra before he threw the rock and did not realize what had

happened until after the threat of imminent bodily harm had

passed. A reasonable person observing what Officer Lopez

observed, therefore, would not have been aware of any threat.

The district court erred in adopting an objective standard that

assumed knowledge beyond what one would reasonably

apprehend in Officer Lopez’s position. 

The district court’s alternative holding that Officer Lopez’s

subjective feeling of fear after the rock hit the gate and landed

UNITED STATES v. ACOSTA-SIERRA 9287
constituted the requisite apprehension of immediate bodily

harm was also in error. The district court found that, at the

time Officer Lopez heard the rock hit the gate behind him, “he

shrugged, was stunned, and was confused by the events,” and

it was not until “he turned and saw the defendant advancing

towards him” that “his confusion turned to feeling threatened

and being scared.” The district court concluded that these

facts were sufficient to demonstrate an expectation of immediate bodily harm because of the “close proximity of time”

between “the bang [Officer Lopez] heard towards his back”

and his feeling of fear. 

[6] In reaching this conclusion, the district court failed to

recognize that the apprehension the officer must feel is apprehension of immediate bodily harm, not apprehension based on

past conduct. See Sheehan v. United States, 896 F.2d 1168,

1171 n.4 (9th Cir. 1990) (noting that, to trigger liability for

assault in torts, “a specific apprehension of imminent battery

is required” and therefore “apprehension of some other harm”

will not suffice); cf. United States v. Jacobs, 632 F.2d 695,

696-97 (7th Cir. 1980) (finding that a victim could not be

placed in apprehension of immediate bodily harm if he did not

see his assailant before being shot, and holding that events

immediately thereafter, including seeing defendant’s gun

pointed at the victim, constituted a separate assault based on

placing the victim in fear of a second gun shot); see generally

Webster’s Third New Int’l Dictionary, 1130, 1132

(unabridged ed. 1993) (defining “imminent” as “ready to take

place: near at hand: impending” and defining “impend” as “to

threaten from near at hand or as in the immediate future”).5

5The justification for requiring that assault be based on a threat of

immediate bodily injury relates to common law theories of self-defense.

If an individual believes an attack is imminent, resorting to defensive

action is justified. See Price, 156 F. at 953; see generally Sheehan, 896

F.2d at 1171 n.4 (noting that, historically, “[a] cause of action for assault

[in torts] was provided to preserve the ‘king’s peace’ by punishing conduct likely to inspire retaliation by one who perceives himself threatened

by imminent battery”). In contrast, if the threatening conduct is completed

prior to the victim realizing what has transpired, the threat of bodily harm

has ceased and defensive action is not necessary, and therefore unjustified,

to avoid danger. 

9288 UNITED STATES v. ACOSTA-SIERRA
Here, the district court never found that Acosta-Sierra’s

rock-throwing conduct caused Officer Lopez to fear imminent

bodily harm. In fact, the district court specifically found that

Officer Lopez “was not in fear when he heard the bang of the

object.” Although Officer Lopez stated that he started to feel

“threatened and scared of the situation that was going on”

soon after seeing the rock fall to the ground, this general feeling of fear or unease is not the same as apprehension of an

imminent battery due to Acosta-Sierra’s throwing of the rock.

See Sheehan, 896 F.2d at 1171 n.4. Nor is there any evidence

that Officer Lopez feared that Acosta-Sierra would attack him

again. When Officer Lopez turned to observe Acosta-Sierra

“advancing on him,” Acosta-Sierra was still six to seven car

lengths away and did not appear to be carrying any rocks or

other weapons in his hands. He therefore did not have an “apparent present ability” to immediately cause bodily harm to

Officer Lopez. Chapman, 528 F.3d at 1219-20.6

[7] Because Officer Lopez did not become aware of the

threat until after it had dissipated, a reasonable person in his

position would not have apprehended immediate bodily

injury. Cf. United States v. Havelock, 664 F.3d 1284, 1304

(9th Cir. 2012) (Reinhardt, J., concurring) (noting, in the context of threatening communications, that “[a] threat can refer

only to a future, not a past, act”). Accordingly, the district

court erred in concluding that Acosta-Sierra’s rock-throwing

conduct constituted assault under the “reasonable apprehension of harm” prong of common law assault.

2. Criminal Intent

[8] In finding Acosta-Sierra guilty of assault under the

6Because we conclude that a reasonable official in Officer Lopez’s position would not have feared immediate bodily harm based on AcostaSierra’s post-rock throwing conduct, it is unnecessary to address AcostaSierra’s argument that the district court’s reliance on such conduct created

a prejudicial variance. 

UNITED STATES v. ACOSTA-SIERRA 9289
“reasonable apprehension of harm” prong, the district court

also erred by holding that the government “need not . . .

prove[ ]” that Acosta-Sierra intentionally used force against

Officer Lopez, and thereby reading criminal intent out of Section 111 completely. To sustain a conviction for a violation of

Section 111, however, we “require[ ] intent to assault.” Juvenile Female, 566 F.3d at 947.

[9] Although the standard for mental culpability under

Section 111 has been a source of confusion and debate within

and beyond our Circuit, see, e.g., Jim, 865 F.2d at 213, we

have long held that mens rea, “the evil purpose or mental culpability which was the essential mental component of

common-law assault and battery,” is an essential element of

forcible assault under Section 111. Kartman, 417 F.2d at 895;

see also Feola, 420 U.S. at 685 (holding that a defendant need

not know that his victim is a federal officer to be held liable

under Section 111, so long as “he nonetheless knows from the

very outset that his planned course of conduct is wrongful”).

[10] By finding Acosta-Sierra guilty of felony assault

without finding facts sufficient to justify that Acosta-Sierra

“knowingly and intentionally and forcibly” assaulted Officer

Lopez, as charged in the indictment, the district court essentially turned this crime into a strict liability offense. However,

“[f]orcible assault [pursuant to Section 111] clearly does not

come within the class of ‘public welfare offenses’ which the

legislature might wish to punish regardless of the actor’s

intent.” Kartman, 417 F.2d at 895 n.4 (citations omitted). The

district court erred in holding that assault under the “reasonable apprehension of harm” prong did not require a finding

that Acosta-Sierra intentionally used force against Officer

Lopez.

3. Rule 29 Motion

[11] Acosta-Sierra also claims that the district court erred

in denying his Rule 29 motion for a judgment of acquittal

9290 UNITED STATES v. ACOSTA-SIERRA
based on insufficiency of the evidence. Although we reverse

his conviction on Count 2 because the district court applied an

incorrect standard of law, we must address the sufficiency of

the evidence supporting it, because if the evidence were insufficient, retrial would be barred by the Double Jeopardy

Clause. See United States v. Recio, 371 F.3d 1093, 1106 (9th

Cir. 2004). On the other hand, the Double Jeopardy Clause

“does not prevent the government from retrying a defendant

who succeeds in getting his conviction set aside . . . because

of some error in the proceedings leading to conviction.” Lockhart v. Nelson, 488 U.S. 33, 38-39 (1988). We disagree with

Acosta-Sierra that there was insufficient evidence to support

his conviction for assault under Count 2.

Count 2 of the indictment charged Acosta-Sierra with

“knowingly and intentionally and forcibly assault[ing]” Officer Lopez by “throw[ing] baseball size rocks at Agent Lopez

while he was engaged in the performance of his official

duties” and using “dangerous and deadly weapons, to wit,

rocks” in committing the offense. The indictment did not,

therefore, distinguish between the two types of common law

assault. As discussed, the district court erred in holding that

Acosta-Sierra’s rock-throwing constituted assault under the

“reasonable apprehension of harm” prong of common law

assault because the district court applied an overly-broad standard of objective reasonableness, overlooked the requirement

that Officer Lopez fear immediate bodily injury, and failed to

find that Acosta-Sierra acted with the requisite criminal

intent.

Nonetheless, we find that there was sufficient evidence to

convict Acosta-Sierra of assault in violation of Section 111(a)

and (b) under the attempted battery prong. The government

presented evidence that Acosta-Sierra hurled “with all of his

might” a baseball-size rock toward Officer Lopez, “missing

him by one to two feet at a point closest to Lopez’s head.”

Viewing the evidence in the light most favorable to the prosecution, a rational trier of fact could find based on circumstanUNITED STATES v. ACOSTA-SIERRA 9291
tial evidence that Acosta-Sierra saw Agent Lopez crossing

between the empty passenger lanes and deliberately threw the

rock at him. See United States v. Sommerstedt, 752 F.2d 1494,

1496 (9th Cir. 1985); cf. Feola, 420 U.S. at 684-86; see generally United States v. Beltran-Garcia, 179 F.3d 1200, 1205

n.4 (9th Cir. 1999) (recognizing that it is permissible for a fact

finder to infer that a person intends the natural and probable

consequences of acts done knowingly). Our cases make clear

that it is irrelevant under the attempted battery prong that the

rock did not strike Officer Lopez, see Chapman, 528 F.3d at

1219, and that Officer Lopez did not apprehend immediate

bodily harm, see Lewellyn, 481 F.3d at 697; Skeet, 665 F.2d

at 987. Acosta-Sierra concedes that Officer Lopez was

engaged in the performance of his official duties at the time

of the incident, see 18 U.S.C. § 111(a)(1), and does not challenge the district court’s holding that the rock constituted a

deadly or dangerous weapon, see 18 U.S.C. § 111(b). 

[12] Viewing the evidence in the light most favorable to

the prosecution, we conclude that a rational trier of fact could

have found beyond a reasonable doubt that Acosta-Sierra

made a willful attempt to inflict injury upon Officer Lopez,

see Chapman, 528 F.3d at 1219-20, and that he did so with

the requisite “intent to assault,” Juvenile Female, 566 F.3d at

947. Because the Double Jeopardy Clause does not bar retrial

in these circumstances, see Cote, 51 F.3d at 182-83, we

remand for further proceedings consistent with this opinion.

B. Count 3

1. Evidence of Diminished Capacity

Acosta-Sierra contends that the district court erred when it

held that Section 111 is a general intent crime and, as a result,

impermissibly precluded Acosta-Sierra’s diminished capacity

defense. See United States v. Twine, 853 F.2d 676, 679 (9th

Cir. 1988) (holding that “diminished capacity, like voluntary

9292 UNITED STATES v. ACOSTA-SIERRA
intoxication, generally is only a defense when specific intent

is at issue”). 

[13] Acosta-Sierra’s argument is foreclosed by United

States v. Jim, where we held that assault under Section 111 is

a general intent crime. 865 F.2d at 215. The defendant in Jim

was charged with three counts of assault on a federal officer

with a deadly weapon following an extended car chase in

which the defendant fired four gun shots at police officers. Id.

at 212. In determining whether the trial court erred in precluding the defendant from instructing the jury on the defense of

voluntary intoxication, we analyzed Section 111 based on the

elements of the statute and its purpose. First, we noted that

Section 111 appears to be a specific intent crime because the

common law definition of assault requires proving “willfulness.” Id. at 213 (citing United States v. Drew, 722 F.2d 551,

553 (9th Cir. 1983), for the proposition that “the element of

wilfulness renders an offense a specific intent crime”). We

then considered the statute in light of Congress’s purpose, and

concluded that applying a general intent test would better

serve the congressional purpose of “protect[ing] federal officers in the exercise of their official duties.” Id. at 215. 

Acosta-Sierra concedes that Jim deemed assault on a federal officer to be a general intent offense, but argues that our

decision in United States v. Chapman undermined the legal

analysis in Jim and, in so doing, changed the mens rea landscape for Section 111 offenses. In Chapman, we did not

address criminal intent at all. Chapman, 528 F.3d 1215. However, we did consider the plain language of the statute, and

determined that, by using the term “simple assault” in Section

111(a), “Congress strongly suggested that an assault was

required for a Section 111 conviction.” Id. at 1221; but see

Jim, 865 F.2d at 214 (relying, in part, on the fact that Section

111 prohibits “resisting, impeding, intimidating, and interfering with a federal officer,” in addition to prohibiting assault,

to conclude that, “Congress intended to prevent interference

with federal functions, not just assault on federal officers.”)

UNITED STATES v. ACOSTA-SIERRA 9293
(emphasis added). By construing Section 111 based only on

the plain language of the statute, Acosta-Sierra contends that

we implicitly rejected the congressional purpose analysis in

Jim and only Jim’s analysis based on the elements of the

offense remains intact. Consequently, Acosta-Sierra argues

that Section 111 must now be construed to require a showing

of specific intent. We disagree. 

[14] Although our decision in Chapman clarified the type

of conduct prohibited by Section 111, it did not make Section

111’s congressional purpose wholly irrelevant to resolving

other ambiguities in this “inartfully drafted” statute, Chapman, 528 F.3d at 1218, such as the requisite level of mens rea.

In resolving the complicated question of whether Section 111

requires proving specific or general intent, the majority of

Jim’s congressional purpose analysis was based on the

Supreme Court’s decision in United States v. Feola, which

noted that, in passing Section 111, “Congress intended to protect both federal officers and federal functions.” Jim, 865 F.2d

at 214 (quoting Feola, 420 U.S. at 679) (internal quotation

marks omitted). Because Jim is amply supported by the

Supreme Court’s reasoning in Feola, it has not been effectively overruled by Chapman. 

Therefore, we do not find that our decisions in Chapman

and Jim are clearly irreconcilable. See Miller v. Gammie, 335

F.3d 889, 892-93 (9th Cir. 2003) (en banc) (holding that only

when “the reasoning or theory of our prior circuit authority is

clearly irreconcilable with the reasoning or theory of intervening higher authority, [should a three-judge panel] consider

itself bound by the later and controlling authority, and . . .

reject the prior circuit opinion as having been effectively

overruled.”). 

[15] Because we are bound by our prior holding in Jim, the

district court did not err in precluding Acosta-Sierra from

introducing evidence as part of a diminished capacity defense.

See also Vela, 624 F.3d at 1156 (holding, post-Chapman, that

9294 UNITED STATES v. ACOSTA-SIERRA
Section 111 is a general intent crime to which diminished

capacity is not a permissible defense).

2. Evidence of Self-Defense Theory

Finally, Acosta-Sierra argues that the district court erred

when it excluded his mental health evidence in support of a

self-defense theory on Count 3. We disagree.

[16] For purposes of Section 111, we have recognized that

an individual may make out an affirmative defense of selfdefense against a federal law enforcement official who uses

excessive force in a narrow range of circumstances. See

United States v. Span, 970 F.2d 573, 577 (9th Cir. 1992); see

also id. at 580 (noting that an individual has a limited right

to offer reasonable resistance to arrest that is triggered by the

officer’s bad faith or provocative conduct). To do so, however, a defendant must offer evidence to show: “(1) a reasonable belief that the use of force was necessary to defend

himself or another against the immediate use of unlawful

force and (2) the use of no more force than was reasonably

necessary in the circumstances.” United States v. Urena, 659

F.3d 903, 907 (9th Cir. 2011) (quoting United States v. Biggs,

441 F.3d 1069, 1071 (9th Cir. 2006)). Moreover, an individual who is the attacker cannot make out a claim of selfdefense as a justification for an assault. Id.

Here, Acosta-Sierra sought to introduce evidence through

expert testimony that, due to a psychotic breakdown related

to his schizophrenia, he honestly believed that jail officials,

marshals, and others were trying to poison his food and kill

him at the time of the assault on Officer Burrola. 

In support of this position, Acosta-Sierra relies on United

States v. Sanchez-Lima, 161 F.3d 545 (9th Cir. 1998), to

argue that mental health evidence is relevant and admissible

if it demonstrates why a defendant “reasonably believed”

force was about to be used on him. In Sanchez-Lima, the

UNITED STATES v. ACOSTA-SIERRA 9295
defendant submitted evidence that, following an attack by a

border patrol agent who Sanchez-Lima did not realize was a

federal official, another border patrol agent jumped out at

Sanchez-Lima from behind some shrubbery, in the dark, without identifying himself. Id. at 547, 549. On this basis, “a rational jury could conclude that Sanchez-Lima reasonably

believed that he was about to receive another beating.” Id. At

549.

In contrast, the district court refused to allow Acosta-Sierra

to admit mental health evidence on his self-defense theory

because no objectively reasonable person in Acosta-Sierra’s

position would believe self-defense to be necessary to prevent

an imminent attack from Officer Burrola. As noted by the district court, when Officer Burrola approached Acosta-Sierra to

handcuff him and escort him to court, there was no use of

force, let alone any excessive force, from which one might

reasonably suggest that a cognizable theory of self-defense

would lie. In fact, the evidence demonstrated that AcostaSierra was the attacker. 

[17] While mental health evidence would have explained

why Acosta-Sierra subjectively believed that self-defense was

necessary under the circumstances, it would not have supported the proposition that his actions were objectively reasonable. See, e.g., People v. Goetz, 68 N.Y.2d 96, 112 (1986)

(holding that the “he reasonably believes” language in selfdefense statute “retains an objective element” and thus the

court below erred in saying it merely required the defendant’s

belief to be “reasonable to him”). 

This objective standard is particularly important in the

penological context due to “the delicate situation faced by

correctional officers, who are required to make snap judgments regarding the ‘very real threats [that] unrest presents to

inmates and prison officials alike, in addition to the possible

harms to inmates against whom force might be used.’ ”

9296 UNITED STATES v. ACOSTA-SIERRA
United States v. Gore, 592 F.3d 489, 490, 493 (4th Cir. 2010)

(quoting Whitley v. Albers, 475 U.S. 312, 320 (1986)). 

[18] Therefore, the district court did not abuse its discretion in refusing to admit mental health evidence in support of

Acosta-Sierra’s theory of self-defense.

IV. CONCLUSION

The judgment of conviction on Count 2 is reversed, and the

judgment of conviction on Count 3 is affirmed. We remand

for further proceedings consistent with this opinion.

REVERSED in part, AFFIRMED in part,

REMANDED.

UNITED STATES v. ACOSTA-SIERRA 9297