United States Court of Appeals

FOR THE DISTRICT OF COLUMBIA CIRCUIT

Argued February 22, 2016 Decided June 10, 2016

No. 14-3060

UNITED STATES OF AMERICA,

APPELLEE

v.

QUEEN NWOYE,

APPELLANT

Appeal from the United States District Court

for the District of Columbia

(No. 1:07-cr-00012-1)

A.J. Kramer, Federal Public Defender, argued the cause 

and filed the briefs for appellant.

Karen P. Seifert, Assistant U.S. Attorney, argued the 

cause for appellee. On the brief were Elizabeth Trosman, 

Frederick Yette, James Sweeney, and David P. Saybolt, 

Assistant U.S. Attorneys.

Before: KAVANAUGH, Circuit Judge, and EDWARDS and 

SENTELLE, Senior Circuit Judges.
2

Opinion for the Court filed by Circuit Judge

KAVANAUGH, with whom Senior Circuit Judge EDWARDS

joins.

Dissenting opinion filed by Senior Circuit Judge

SENTELLE.

KAVANAUGH, Circuit Judge: A woman named Queen 

Nwoye was convicted of conspiring with her boyfriend, 

Adriane Osuagwu, to extort money from a prominent doctor

with whom Nwoye had previously had an affair. At trial, 

Nwoye testified that she acted under duress: She said that 

Osuagwu repeatedly beat her and forced her to participate in 

the extortion scheme. Despite asserting a duress defense 

based on Osuagwu’s repeated abuse of Nwoye, Nwoye’s 

counsel did not introduce expert testimony on battered woman 

syndrome. At the close of trial, Nwoye’s counsel requested a 

jury instruction on duress, but the District Court denied the 

request. A jury then convicted Nwoye of conspiracy to 

commit extortion.

On direct appeal, Nwoye challenged the District Court’s 

failure to instruct the jury on duress. This Court rejected the 

challenge, with Judge Tatel dissenting. But the Court

indicated that it was rejecting Nwoye’s challenge in part 

because Nwoye had failed to introduce expert testimony on 

battered woman syndrome. Such expert testimony, the Court

suggested, may have entitled Nwoye to a duress instruction.

Nwoye then moved to vacate the conviction based on 

alleged ineffective assistance of trial counsel. A claim of 

ineffective assistance of counsel requires the defendant to 

show (i) that counsel’s performance was constitutionally 

deficient and (ii) that the ineffective assistance prejudiced the 

defendant. On the first prong, the deficiency prong, Nwoye

claimed that competent trial counsel would have introduced
3

expert testimony on battered woman syndrome. On the 

second prong, the prejudice prong, Nwoye claimed that such 

expert testimony would have led the District Court to instruct 

the jury on duress. And Nwoye further argued that the 

combination of the expert testimony and the duress instruction 

would have created a reasonable doubt respecting her guilt.

The District Court denied Nwoye’s ineffectiveassistance-of-counsel claim. The District Court held that 

Nwoye was not prejudiced by trial counsel’s failure to 

introduce expert testimony on battered woman syndrome. 

The District Court therefore did not need to (and did not) 

decide whether counsel’s performance was constitutionally

deficient. 

Although the prejudice question is close, we see it 

differently than the District Court did. We conclude that 

Nwoye was prejudiced by trial counsel’s failure to introduce

expert testimony on battered woman syndrome. We therefore

reverse the judgment of the District Court, and we remand so 

that the District Court may decide whether Nwoye’s counsel 

was constitutionally deficient in failing to present such 

testimony. 

I

A

In January 2007, a woman named Queen Nwoye was 

indicted for conspiring with her then-boyfriend, Adriane 

Osuagwu, to extort money from Ikemba Iweala. Iweala was a 

prominent doctor. He and Nwoye had previously had an 

affair. Over the course of 49 days in 2006, Osuagwu and 

Nwoye repeatedly threatened Iweala that they would 

publicize his prior relationship with Nwoye unless Iweala 

paid them. Their threats were effective. Iweala made six 
4

separate payments to Osuagwu and Nwoye, totaling almost 

$200,000.

At Nwoye’s trial, Nwoye admitted to engaging in the 

alleged extortion but testified that Osuagwu had coerced her

participation through his physically abusive and controlling 

behavior. According to Nwoye, her relationship with 

Osuagwu turned abusive shortly after they started dating in 

2005. Osuagwu would frequently slap Nwoye with his hand, 

hit her with his shoe, and beat her on her face and body. 

Later, Osuagwu’s physical violence escalated. Osuagwu beat

Nwoye when she initially refused to introduce him to Iweala. 

Whenever she objected to the extortion, Osuagwu would beat 

her “like a drum.” And on one occasion when Nwoye did not 

play her part in the extortion scheme, Osuagwu slapped 

Nwoye and threatened to “strangle” and “kill” her if the 

scheme were exposed.

Nwoye further testified that Osuagwu exerted financial 

and psychological control over her. Osuagwu forced Nwoye 

to hand over her ATM card and PIN. In addition, Nwoye and 

her children lived with Osuagwu at Osuagwu’s home in 

Maryland. Nwoye testified that Osuagwu – the only person 

who knew that she lived at the house – would often threaten 

to kill Nwoye and bury her inside the house. Nwoye also 

testified that she was afraid to report Osuagwu to the police 

because Osuagwu had told her that he was a former FBI 

agent.

At the same time, Nwoye’s testimony revealed that 

Osuagwu did not have direct physical control over Nwoye at 

all times. While Nwoye attended nursing school or worked at 

a hospital for three days a week, she was apart from

Osuagwu. And Osuagwu spent at least a few days in 

California while Nwoye remained in Maryland. 
5

But even while they were apart, Osuagwu constantly 

monitored Nwoye. He forced Nwoye to keep her phone with

her and demanded that she answer promptly, even going so 

far as to require Nwoye to wear a Bluetooth earpiece during 

class at nursing school.

B

Despite the significant evidence of Nwoye’s abusive 

relationship with Osuagwu, Nwoye’s trial counsel did not 

seek to introduce expert testimony on battered woman

syndrome. 

Battered woman syndrome is a term that was coined by 

Dr. Lenore Walker in the late 1970s to describe the 

psychological and behavioral traits common to women who 

are exposed to severe, repeated domestic abuse. See LENORE 

E. WALKER, THE BATTERED WOMAN SYNDROME (1984); 

LENORE E. WALKER, THE BATTERED WOMAN (1979). Dr. 

Walker’s theory was that women subject to cyclical domestic 

abuse develop psychological paralysis – or “learned 

helplessness” – that renders them unable to escape abusive 

relationships. See WALKER, BATTERED WOMAN SYNDROME

at 86-97.1

 

1 Although the majority of domestic violence victims are 

women, some cases involve victims who are men. See Department 

of Justice, Bureau of Justice Statistics, Intimate Partner Violence, 

1993-2010 1 (Nov. 2012, rev. Sept. 2015) (“From 1994 to 2010, 

about 4 in 5 victims of intimate partner violence were female.”). 

Some scholars have advocated abandoning the term “battered 

woman syndrome” in favor of the label “battering and its effects.” 

See, e.g., Mary Ann Dutton, Update of the “Battered Woman 

Syndrome” Critique, National Online Resource Center on Violence 

Against Women (Aug. 2009). We use the term “battered woman 

syndrome” in this opinion because the term is commonly used by 
6

Since the advent of Dr. Walker’s influential research, 

courts have admitted expert testimony on battered woman 

syndrome to support claims of duress and self-defense. See

Janet Parrish, Trend Analysis: Expert Testimony on Battering 

and Its Effects in Criminal Cases, in DEPARTMENT OF JUSTICE

ET AL., THE VALIDITY AND USE OF EVIDENCE CONCERNING 

BATTERING AND ITS EFFECTS IN CRIMINAL TRIALS pt. II, at 19, 

21-22, 28 (1996) (hereinafter DOJ REPORT).

 C

At Nwoye’s trial, Nwoye’s counsel did not present expert 

testimony on battered woman syndrome. Counsel instead 

staked Nwoye’s duress defense entirely on Nwoye’s own trial 

testimony. At the close of trial, Nwoye’s counsel requested a 

jury instruction on duress. To be entitled to an instruction on 

duress, Nwoye had to present sufficient evidence (i) that she 

acted under an unlawful threat of imminent death or serious 

bodily injury and (ii) that there was no reasonable alternative

to participating in the extortion scheme. See United States v. 

Jenrette, 744 F.2d 817, 820-21 (D.C. Cir. 1984).

The District Court ruled that Nwoye had not presented 

sufficient evidence on the second prong of duress – the noreasonable-alternative prong – and therefore declined to give

the duress instruction. The jury then convicted Nwoye of 

conspiracy to commit extortion, and the District Court 

sentenced Nwoye to 20 months in prison, followed by three 

years of supervised release.

2

 

courts and because it describes the alleged circumstances in this 

case.

2

For his part, Osuagwu pled guilty to conspiracy and was 

sentenced to 22 months in prison.
7

Nwoye appealed, challenging the District Court’s 

decision not to give the duress instruction. This Court 

affirmed. United States v. Nwoye, 663 F.3d 460 (D.C. Cir. 

2011). The Court explained that Nwoye had a number of 

reasonable alternatives to participating in the extortion 

scheme, including reporting Osuagwu to police or to friends 

and co-workers when she was at school or work, away from 

Osuagwu. Id. at 462-65.

The Court also stressed that although Nwoye had testified 

about the abuse she suffered, she failed to present “other usual 

indicia supporting a BWS defense – expert witnesses 

testifying to the effects of isolation, financial dependence, or 

estrangement from family members.” Id. at 465. Therefore, 

the Court concluded that Nwoye was not entitled to a jury 

instruction on duress.

Judge Tatel dissented. In his view, Nwoye’s testimony 

concerning Osuagwu’s threats and abuse amounted to “more 

than enough evidence to have warranted a duress instruction.” 

Id. at 468.

 D

In 2013, after the termination of her supervised release,

Nwoye filed a motion to vacate her conviction.3 Nwoye

 

3 On appeal, Nwoye has characterized her post-conviction 

motion as a petition for a writ of coram nobis. “A petition for a 

writ of coram nobis provides a way to collaterally attack a criminal 

conviction for a person . . . who is no longer ‘in custody’ and 

therefore cannot seek habeas relief under 28 U.S.C. § 2255 or 

§ 2241.” Chaidez v. United States, 133 S. Ct. 1103, 1106 n.1 

(2013). The Government does not dispute that a petition for a writ 

of coram nobis is an appropriate way for Nwoye to seek redress for 
8

claimed that her trial counsel was constitutionally ineffective 

because counsel failed to call an expert witness to testify 

about battered woman syndrome. To establish that her 

counsel was constitutionally ineffective, Nwoye had to prove 

(i) that her counsel’s performance was constitutionally 

deficient and (ii) that counsel’s ineffective assistance 

prejudiced her. Strickland v. Washington, 466 U.S. 668, 687

(1984).

The District Court held an evidentiary hearing to allow 

Nwoye to present the expert testimony on battered woman 

syndrome that Nwoye argued should have been offered at 

trial. At the hearing, Nwoye’s expert – Dr. Carole Giunta –

testified extensively about battered woman syndrome in 

general. Dr. Giunta also opined that Nwoye’s relationship 

with Osuagwu exhibited the “classic dynamics” of a battering 

relationship.

After considering this new evidence, the District Court

denied Nwoye’s motion to vacate her conviction. United 

States v. Nwoye, 60 F. Supp. 3d 225 (D.D.C. 2014). Applying 

the two-part test for ineffective-assistance claims, the District 

Court ultimately did not decide whether trial counsel’s alleged 

failures rose to the level of a constitutional deficiency. 

Instead, the District Court decided that Nwoye was, in any 

event, not prejudiced by the lack of expert testimony on 

battered woman syndrome. The District Court reasoned that 

such testimony still would not have satisfied the second prong 

of duress – the no-reasonable-alternative prong – and that the 

testimony therefore would not have entitled Nwoye to a jury 

instruction on duress. Id. at 236-42. For that reason, the 

 

her claim of ineffective assistance of counsel. See United States v. 

Newman, 805 F.3d 1143, 1146 (D.C. Cir. 2015).
9

District Court held that Nwoye had not made out a successful 

claim of ineffective assistance of counsel.

II

Nwoye claims that her trial counsel was constitutionally 

ineffective because counsel failed to present expert testimony 

on battered woman syndrome. To reiterate, a defendant 

claiming ineffective assistance of counsel must show that (i) 

“counsel’s representation fell below an objective standard of 

reasonableness” and (ii) “the deficient performance 

prejudiced the defense.” Strickland v. Washington, 466 U.S. 

668, 687-88 (1984). The District Court held that trial

counsel’s failure to present expert testimony on battered 

woman syndrome was not prejudicial. The District Court thus

did not need to (and did not) decide whether trial counsel’s 

failure to present such testimony was constitutionally 

deficient. 

On appeal, therefore, the only issue for us to decide is 

whether the failure of Nwoye’s trial counsel to present expert 

testimony on battered woman syndrome was prejudicial. If 

so, then we must remand for the District Court to determine 

whether trial counsel was constitutionally deficient in failing 

to introduce such testimony. If not, then we must affirm. We 

review de novo the District Court’s denial of Nwoye’s claim 

of ineffective assistance of counsel, including the question 

whether Nwoye was prejudiced by her counsel’s allegedly 

deficient performance. See United States v. Abney, 812 F.3d 

1079, 1086-87 (D.C. Cir. 2016).

4

 Although the dissent 

 

4 Of course, we still review for clear error any findings of 

historical fact embedded in the District Court’s conclusions on 

deficient performance and prejudice. See Payne v. Stansberry, 760 

F.3d 10, 13 (D.C. Cir. 2014); see also HARRY T. EDWARDS, LINDA 

A. ELLIOTT, & MARIN K. LEVY, FEDERAL STANDARDS OF REVIEW:
10

suggests that we should give some deference to the District 

Court, our case law is clear that the standard of review is de 

novo.

To establish prejudice, Nwoye must demonstrate “a 

reasonable probability that, absent the errors, the factfinder 

would have had a reasonable doubt respecting guilt.” 

Strickland, 466 U.S. at 695. To demonstrate a reasonable 

probability, Nwoye “need not show that counsel’s deficient 

conduct more likely than not altered the outcome in the case.” 

Id. at 693. She must demonstrate only “a probability 

sufficient to undermine confidence” in the verdict. Id. at 694. 

Nwoye’s prejudice argument proceeds in two steps: 

First, Nwoye argues that expert testimony on battered woman 

syndrome would have entitled her to a jury instruction on the 

defense of duress. Second, she claims that a duress 

instruction, together with the expert testimony on battered 

woman syndrome, would have created a “reasonable 

probability” that the jury “would have had a reasonable doubt 

respecting guilt.” Id. at 695. Nwoye must succeed on both 

arguments to establish prejudice.

We conclude first that expert testimony on battered 

woman syndrome would have entitled Nwoye to a jury 

instruction on duress. And we conclude further that a duress

instruction, together with the expert testimony, would have 

created a reasonable probability that the jury would have had 

a reasonable doubt respecting Nwoye’s guilt.

 

REVIEW OF DISTRICT COURT DECISIONS AND AGENCY ACTIONS 1

(2d ed. Supp. 2015) (When “courts determine that a particular 

mixed question of law and fact should be treated as a question of 

law and reviewed de novo, subsidiary findings of fact are properly 

reviewed under the clearly erroneous standard of review.”).
11

A

As this Court stated on Nwoye’s direct appeal, a

defendant is entitled to a jury instruction on any recognized 

affirmative defense “if there is sufficient evidence from which 

a reasonable jury could find for the defendant on that theory.” 

United States v. Nwoye, 663 F.3d 460, 462 (D.C. Cir. 2011)

(internal quotation marks omitted). To obtain an instruction 

on the affirmative defense of duress, a defendant must

produce sufficient evidence (i) that “she acted under an 

unlawful threat of imminent death or serious bodily injury,” 

and (ii) that there was no “reasonable, legal alternative to 

committing the crime.” Id. (internal quotation marks 

omitted).

On direct appeal, this Court held that the evidence 

Nwoye presented at trial was insufficient to support a duress 

instruction. Id. at 462-65. In so ruling, however, the Court

emphasized that Nwoye had not introduced expert testimony 

on battered woman syndrome. Id. at 465. The Court 

indicated (or at least implied) that Nwoye might have been 

entitled to a duress instruction had she introduced such 

testimony. We now must decide that question.

The question, put simply, is whether expert testimony on 

battered woman syndrome would have moved the evidentiary 

needle enough to entitle Nwoye to a duress instruction. To 

answer that question, we must initially assess whether, in 

general, expert testimony on battered woman syndrome can 

be admissible to prove duress – that is, whether it can be 

reliable and can be relevant to the duress defense. If so, then 

we next must assess whether the particular expert testimony 

proffered by Nwoye in her post-conviction proceeding was 

reliable and would have provided relevant evidence at 

Nwoye’s trial. Finally, if Nwoye’s expert testimony would 
12

have been admissible, we must determine whether the 

introduction of such testimony at Nwoye’s trial would have 

entitled her to a jury instruction on duress. 

We now address those three questions in turn.

1

For expert testimony to be admissible in federal court, it 

must be both reliable and relevant. See FED. R. EVID. 702; 

Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579, 

589 (1993).

As to reliability, trial judges possess “considerable 

leeway in deciding in a particular case how to go about 

determining whether particular expert testimony is reliable.” 

Kumho Tire Co. v. Carmichael, 526 U.S. 137, 152 (1999). At 

bottom, though, the expert’s opinion must have “a reliable 

basis in the knowledge and experience of his discipline.” Id.

at 148.

The Government does not dispute that expert testimony 

on battered woman syndrome can be reliable. And several

courts of appeals have permitted the admission of expert 

testimony on battered woman syndrome. See United States v. 

Young, 316 F.3d 649, 656-59 (7th Cir. 2002); Arcoren v. 

United States, 929 F.2d 1235, 1241 (8th Cir. 1991). None has 

held that such testimony is categorically unreliable, so far as 

we are aware. Given the history of expert testimony on this 

subject and the extensive literature, we too agree that expert 

testimony on battered woman syndrome can be reliable, 

assuming of course that the expert can demonstrate sufficient 

expertise to meet the usual requirements for experts to testify 

on a subject. 
13

To be admissible in support of a duress defense, expert 

testimony on battered woman syndrome must also be relevant

to proving duress. Most courts that have considered the 

question – especially in recent years – have recognized that 

expert testimony on battered woman syndrome can be 

relevant to prove duress. See Dando v. Yukins, 461 F.3d 791, 

801 (6th Cir. 2006); United States v. Dixon, 413 F.3d 520, 

524 & n.3 (5th Cir. 2005); United States v. Ceballos, 593 F. 

Supp. 2d 1054, 1060-62 (S.D. Iowa 2009); United States v. 

Marenghi, 893 F. Supp. 85, 91-97 (D. Me. 1995); Wonnum v. 

State, 942 A.2d 569, 572-73 (Del. 2007); Commonwealth v. 

Pike, 726 N.E.2d 940, 948 (Mass. 2000) (expert testimony 

assumed to be relevant to prove duress); People v. Romero, 13 

Cal. Rptr. 2d 332 (1992), rev’d on other grounds, 883 P.2d 

388 (Cal. 1994); but see United States v. Willis, 38 F.3d 170, 

174-77 (5th Cir. 1994); State v. B.H., 870 A.2d 273, 289-91

(N.J. 2005) (expert testimony irrelevant to reasonableness of 

duress defense).

We agree with the majority of the courts that expert 

testimony on battered woman syndrome can be relevant to the 

duress defense. The reason, put simply, is that the duress

defense requires a defendant to have acted reasonably under 

the circumstances, and expert testimony can help a jury assess 

whether a battered woman’s actions were reasonable.

Reasonableness is the touchstone of a duress defense. To 

satisfy the first prong of the duress defense, the defendant 

must have acted under the influence of a reasonable fear of 

imminent death or serious bodily harm at the time of the 

alleged crime. See 2 WAYNE R. LAFAVE, SUBSTANTIVE

CRIMINAL LAW § 9.7(b) (2d ed. 2003) (“the danger need not 

be real; it is enough if the defendant reasonably believes it to 

be real”); see also United States v. Jenrette, 744 F.2d 817, 

820-21 (D.C. Cir. 1984). And to satisfy the second prong of 
14

the defense, there must have been no “reasonable, legal 

alternative to committing the crime.” Nwoye, 663 F.3d at 462 

(emphasis added). Whether an alternative is reasonable turns 

on whether a reasonable person would have availed herself of 

it.

Reasonableness – under both the imminence prong and

the no-reasonable-alternative prong – is not assessed in the 

abstract. Rather, any assessment of the reasonableness of a 

defendant’s actions must take into account the defendant’s 

“particular circumstances,” at least to a certain extent. See id.

at 464; see also Model Penal Code § 2.09 (duress defense 

appropriate whenever a “person of reasonable firmness in his 

situation would have been unable to resist” threat of unlawful 

force) (emphasis added).

The circumstances that juries have historically considered 

in assessing reasonableness have been factors “that 

differentiate the actor from another, like his size, strength, 

age, or health,” as well as facts known to the defendant at the 

time in question, such as the defendant’s knowledge of an 

assailant’s violent reputation. Model Penal Code § 2.09 cmt.

at 375 (1985); Smith v. United States, 161 U.S. 85, 88 (1896). 

On the other hand, courts have typically precluded juries from 

considering factors such as the defendant’s particular 

“psychological incapacity” or her “clarity of judgment, 

suggestibility or moral insight.” Model Penal Code § 2.09

cmt. at 373-74 (1985).

Thus, whether expert testimony on battered woman 

syndrome is relevant to the duress defense turns on whether 

such testimony can identify any aspects of the defendant’s 

“particular circumstances” that can help the jury assess the 

reasonableness of her actions. Examination of the particulars 

of the duress defense shows that expert testimony on battered 
15

woman syndrome can indeed identify relevant aspects of a 

battered woman’s particular circumstances.

With respect to the first prong of the duress defense – the 

imminent-harm prong – women in battering relationships are 

often “hypervigilant to cues of impending danger and 

accurately perceive the seriousness of the situation before 

another person who had not been repeatedly abused might 

recognize the danger.” Lenore E.A. Walker, Battered Women 

Syndrome and Self-Defense, 6 NOTRE DAME J.L. ETHICS &

PUB. POL’Y 321, 324 (1992). Remarks or gestures that may 

seem harmless to the average observer might be reasonably 

understood to presage imminent and severe violence when 

viewed against the backdrop of the batterer’s particular 

pattern of violence. As our colleague Judge Brown stated 

while on the California Supreme Court: “Although a jury 

might not find the appearances sufficient to provoke a 

reasonable person’s fear, they might conclude otherwise as to 

a reasonable person’s perception of the reality when 

enlightened by expert testimony on the concept of 

hypervigilance.” People v. Humphrey, 921 P.2d 1, 17 (Cal. 

1996) (Brown, J., concurring).

Regarding the second prong of the duress defense – the 

no-reasonable-alternative prong – battered women face 

significant impediments to leaving abusive relationships. 

Most importantly, battered women who leave their abusers 

risk a retaliatory escalation in violence against themselves or 

those close to them – sometimes termed “separation abuse.” 

Mary Ann Dutton, Validity of “Battered Woman Syndrome”

in Criminal Cases Involving Battered Women, in DOJ REPORT

pt. I, at 14-15; Desmond Ellis, Post-Separation Woman 

Abuse: The Contribution of Lawyers as “Barracudas,” 

“Advocates,” and “Counsellors,” 10 INT’L J.L. &

PSYCHIATRY 403, 408 (1987). For example, studies have 
16

suggested that women in battering relationships are more 

likely to be killed by their batterers after separating from 

them. See Dutton, Validity of “Battered Woman Syndrome”

in Criminal Cases Involving Battered Women (citing Margo 

Wilson et al., Uxoricide in Canada: Demographic Risk 

Patterns, 35 CANADIAN J. CRIMINOLOGY 263, 263-91 (1993)), 

in DOJ REPORT pt. I, at 14. In addition, batterers often isolate 

their victims and exert financial control over them, rendering 

separation a significant burden. See LENORE E. WALKER, THE 

BATTERED WOMAN, 129-32 (1979). Expert testimony on 

those impediments to separation can help explain why a 

battered woman did not take advantage of an otherwise 

reasonable-sounding opportunity to avoid committing the 

alleged crime.

In short, expert testimony on battered woman syndrome 

can be relevant to both prongs of the duress defense.

Our conclusion is further supported by the decisions of 

the vast majority of courts that have long held that expert 

testimony on battered woman syndrome can be relevant in the 

analogous context of self-defense. See, e.g., Humphrey, 921 

P.2d at 8-9; State v. Kelly, 478 A.2d 364, 377-78 (N.J. 1984); 

Ibn-Tamas v. United States, 407 A.2d 626, 631-35 (D.C. 

1979); see also Janet Parrish, Trend Analysis: Expert 

Testimony on Battering and Its Effects in Criminal Cases, in

DOJ REPORT pt. II, at 19, 28. The elements of self-defense 

are similar to the elements of duress: To establish a claim of 

self-defense in most jurisdictions, a defendant must prove that 

she reasonably believed her use of force was necessary to 

prevent imminent death or serious bodily harm. See 2

LAFAVE, SUBSTANTIVE CRIMINAL LAW § 10.4. Thus, if 

battered woman syndrome can be relevant to prove self-
17

defense (as virtually all courts accept), it likewise should be 

relevant to prove duress.5

In sum, we conclude that expert testimony on battered 

woman syndrome may be admissible as a general matter to 

prove duress because such testimony can be reliable and can 

be relevant to both prongs of the duress defense.

2

The next question is whether expert testimony on 

battered woman syndrome would have been reliable and 

relevant in Nwoye’s case. We conclude that it would have 

been.

To begin with, the Government does not argue that the 

expert testimony from Dr. Giunta that Nwoye proffered in her 

post-conviction proceeding was unreliable. And we have no 

reason to question its reliability.

Nwoye’s expert testimony, moreover, would certainly 

have been relevant to Nwoye’s defense. This Court suggested

as much on Nwoye’s direct appeal by noting the conspicuous 

absence of expert testimony on battered woman syndrome at 

Nwoye’s trial. Nwoye, 663 F.3d at 465. And the Government 

does not dispute that Nwoye’s trial testimony strongly 

 

5 The Government points out that the defenses of self-defense 

and duress are distinct in one sense: Defendants who act in selfdefense often injure morally culpable individuals – the initial 

aggressors – while defendants who act under duress often injure 

blameless third parties. Thus, the Government argues, the duress 

defense should be more narrowly circumscribed in order to protect 

innocent third parties. Maybe so. But the proper response to such a 

fundamental mismatch between the defenses would be to make 

wholesale changes to the duress defense rather than to tweak on an 

ad hoc basis the kinds of evidence that are relevant to duress.
18

suggested that she had been a victim of a battering 

relationship. An expert on battered woman syndrome could 

therefore have helped the jury assess the reasonableness of 

Nwoye’s actions, as we described above.

3

The next question is whether expert testimony on 

battered woman syndrome would have entitled Nwoye to a 

duress instruction in this case. On Nwoye’s direct appeal, 

when we rejected Nwoye’s claim that she was entitled to a 

duress instruction, we pointed specifically to the absence of 

“expert witnesses testifying to the effects of isolation, 

financial dependence, or estrangement from family 

members.” Id. We now conclude that the introduction of 

such testimony at Nwoye’s trial would have entitled Nwoye 

to a duress instruction.

Perhaps most critically, expert testimony on the 

likelihood of retaliatory violence upon separation could have 

provided a plausible explanation for why Nwoye failed to 

extricate herself from the extortion scheme. Nwoye may have 

feared that any attempt to leave Osuagwu would have resulted 

in still greater violence. Moreover, Nwoye may have 

reasonably believed that reporting Osuagwu to the police (or 

others) would have been unlikely to result in his immediate 

arrest and would have therefore placed her at greater risk in 

the interim. Thus, Nwoye’s testimony concerning Osuagwu’s

abuse, supplemented by expert testimony on battered woman 

syndrome, would have constituted “sufficient evidence from 

which a reasonable jury could find” for Nwoye on a theory of 

duress. Id. at 462.

It may be helpful here to take a step back so that the 

reader does not miss the forest for the trees. The concept of 

battered woman syndrome fits this case to a T. A woman was 
19

beaten repeatedly by her boyfriend. Some outsiders may

question why she didn’t just leave her boyfriend. But the

expert testimony would help explain why. For the 

Government to come in now and say that such expert 

testimony, combined with Nwoye’s own testimony about the 

beatings, still would not entitle her to a duress instruction is to 

say in essence that battered woman syndrome does not matter, 

at least in duress cases. We do not agree with that suggestion.

B

To this point, we have concluded that expert testimony 

on battered woman syndrome would have entitled Nwoye to a 

jury instruction on duress. To make out her claim of 

prejudice for purposes of the ineffective-assistance-of-counsel 

inquiry, Nwoye also must show that expert testimony on 

battered woman syndrome, together with the duress 

instruction, would have created a “reasonable probability that 

. . . the result of the proceeding would have been different.” 

Strickland, 466 U.S. at 694. To repeat what we noted above, 

Nwoye does not need to show that the expert testimony and 

the jury instruction “more likely than not” would have 

produced an acquittal. Id. at 693. She must demonstrate only 

“a probability sufficient to undermine confidence” in the 

verdict. Id. at 694.

It can be difficult for a reviewing court (whether a district 

court or a court of appeals) to determine how additional 

evidence or an additional jury instruction would have affected 

a trial. It is inherently a speculative exercise. In this case,

however, we conclude that Nwoye has demonstrated a 

reasonable probability that the jury would have had a 

reasonable doubt respecting her guilt.

At trial, Nwoye admitted to participating in the extortion 

scheme, but said she did so at the direction of Osuagwu. 
20

Based on that testimony, Nwoye’s only possible defense was 

that she acted under duress. But due in part to trial counsel’s 

failure to present expert testimony on battered woman 

syndrome, Nwoye was denied a jury instruction on duress. 

And the District Court specifically precluded Nwoye’s 

counsel from mentioning duress during closing arguments. 

Thus, the failure of Nwoye’s counsel to present expert 

testimony on battered woman syndrome deprived Nwoye of 

any viable legal avenue to acquittal.

With an instruction on duress, together with expert 

testimony on battered woman syndrome, there is at least a

reasonable probability that the jury “would have had a 

reasonable doubt respecting guilt.” Id. at 695. Under very 

similar circumstances, the Sixth Circuit held that an attorney’s 

failure to introduce expert testimony on battered woman 

syndrome prejudiced a defendant who pled guilty to robbery 

and related charges. See Dando v. Yukins, 461 F.3d 791 (6th 

Cir. 2006). The Court reasoned that, if counsel had 

introduced such testimony, the defendant would have had a 

sufficient evidentiary basis for a duress defense. And if the 

defendant had proceeded to trial on a theory of duress, there 

would have been a “likelihood of a favorable outcome at trial” 

such that the defendant’s counsel would not have 

recommended that the defendant take a guilty plea. Id. at 

800-02.

A similar analysis applies here. The duress instruction 

would have given jurors a legal basis upon which to vote not 

guilty. And as discussed above, the expert testimony on 

battered woman syndrome would have supported both 

elements of Nwoye’s duress defense: the imminence of the 

threat and the absence of reasonable alternatives. In addition, 

expert testimony on battered woman syndrome would have 

bolstered the credibility of Nwoye’s testimony about 
21

Osuagwu’s abuse. Jurors faced with testimony from a 

battered woman concerning her abuse and its effects may

doubt the testimony because they do not believe that a woman 

subject to such abuse would stay with her abuser without 

alerting police or others. Expert testimony on battered 

woman syndrome could have helped Nwoye “dispel the 

ordinary lay person’s perception that a woman in a battering 

relationship is free to leave at any time.” Humphrey, 921 P.2d 

at 9; see also Kelly, 478 A.2d at 377.

Those factors add up to a reasonable probability that the 

jury would have had a reasonable doubt respecting guilt if 

expert testimony on battered woman syndrome had been 

presented at Nwoye’s trial. The jury of course could still have 

convicted Nwoye; for example, the jury could have 

disbelieved that Nwoye was telling the truth about the abuse 

in the first place or could have been unpersuaded by the 

expert testimony. But for present purposes on appeal, we 

have no basis to question that Nwoye has told the truth about 

being abused by Osuagwu or to question the expert testimony. 

(The Government does not argue otherwise.) On this record, 

we conclude that Nwoye’s testimony plus the expert 

testimony plus the duress instruction create at least a 

reasonable probability that the jury would have had a 

reasonable doubt respecting guilt. Nwoye was prejudiced by 

her counsel’s failure to present expert testimony on battered 

woman syndrome.

* * *

The District Court considered only the prejudice element 

of the inquiry into ineffective assistance of counsel. The 

District Court found no prejudice. Because we have 

concluded that Nwoye was prejudiced by the failure of her 

trial counsel to introduce expert testimony on battered woman 
22

syndrome, we remand for the District Court to consider in the

first instance the other prong of the ineffective-assistance-ofcounsel standard: whether the performance of Nwoye’s 

counsel fell below an objective standard of reasonableness. If 

counsel’s performance was constitutionally deficient, then 

Nwoye will have established ineffective assistance of counsel

and will be entitled to have her conviction vacated. We 

reverse the judgment of the District Court and remand for 

further proceedings.

So ordered.
SENTELLE, Senior Circuit Judge, dissenting: This case

returns to us on a petition for writ of coram nobis, testing a

criminal conviction previously affirmed by us on direct appeal

in United States v. Nwoye, 663 F.3d 460 (D.C. Cir. 2011). In the

original version, we considered an argument that the trial court

had erred in refusing a defense request for an instruction on a

duress defense. We affirmed the district court, holding that “a

defendant is only entitled to an instruction on a theory of duress

if there is ‘sufficient evidence from which a reasonable jury

could find’ for the defendant on that theory.” Id. at 462 (quoting

United States v. Akhigbe, 642 F.3d 1078, 1083 (D.C. Cir.

2011)). Appellant Nwoye returns, alleging that her trial counsel

rendered ineffective assistance in not presenting expert

testimony on the battered woman syndrome and that she was

prejudiced thereby. The district court was unconvinced, for

reasons expressed in a most able opinion, United States v.

Nwoye, 60 F. Supp. 3d 225 (D.D.C. 2014). My colleagues on

this court reason differently than the district judge. I consider

the district judge’s reasoning the more compelling, and I will

quote from it extensively herein. 

As the majority sets forth, to prevail on the claim for

ineffective assistance of counsel, a petitioning defendant must

establish two elements: “(i) ‘counsel’s representation fell below

an objective standard of reasonableness’ and (ii) ‘the deficient

performance prejudiced the defense.’” Maj. Op. at 9 (quoting

Strickland v. Washington, 466 U.S. 668, 687-88 (1984)). The

district court pretermitted the first question and proceeded to

determine that counsel’s decision not to introduce expert

evidence on the subject of battered woman syndrome was not

prejudicial. Because the majority deems the district court to

have erred in the second part of its decision, we finish in the odd

posture of sending the matter back for the resolution of the

preliminary question. Be that as it may, in my view, the district
2

court did not err on the second prong, so like the majority, I will

find it unnecessary to draw a resolution on the first. 

I would note in passing that in judging the degree, if not the

kind, of counsel’s ineffectiveness, we have never before this

case ruled on the admissibility of expert testimony on battered

woman syndrome to a claimed defense of duress. As the district

court noted, “Traditionally, expert testimony on BWS has been

limited to cases where a defendant puts forward the affirmative

defense of self-defense.” 60 F. Supp. 3d at 237. While I do not

dispute the majority’s extension of the relevance to a duress

defense in appropriate cases, I do find it less than shocking that

the trial counsel did not more vigorously pursue the possibility

in a pioneering posture than would have been the case had the

defense been self defense. Be that as it may, as the majority

notes, the issue directly confronting us is whether counsel’s

failure, construed as ineffective assistance, “prejudiced the

defense.” As the majority states, “Nwoye . . . must show that

expert testimony on battered woman syndrome, together with

the duress instruction, would have created a ‘reasonable

probability that . . . the result of the proceeding would have been

different.’” Maj. Op. at 19 (quoting Strickland, 466 U.S. at 694). 

Like the district court, I am not convinced that she has made this

showing. 

To be entitled to an instruction on the defense of duress, a

defendant must introduce at least some evidence on the two

elements of the defense: (1) that the defendant acted under the

threat of immediate death or serious bodily injury, and (2) that

the defendant had no reasonable legal alternative to committing

the crime. See United States v. Gaviria, 116 F.3d 1498, 1531

(D.C. Cir. 1997). Importantly, in the context of the present case,

defendant must not only show some evidence on these two

elements, she must also establish that if counsel had proffered

the evidence (which he did except for the expert testimony), the
3

judge had allowed it in, and the judge had based instruction

thereon, the jury result would have been different. The record

simply does not support the majority’s conclusion on this cluster

of issues. 

As the district court put it, the trial judge

provided the defendant with ample opportunity to present

evidence in support of both of these necessary elements. 

She permitted the defendant to testify at length about the

abuse that she said she had suffered at the hands of Mr.

Osuagwu. In addition to Ms. Nwoye’s testimony about her

abuse, the judge also heard evidence that undercut

defendant’s theory of the case, including evidence that (1)

Mr. Osuagwu frequently left the D.C.-Maryland area

without her, taking trips to California that lasted days or

weeks; (2) Ms. Nwoye left Mr. Osuagwu and returned to

her husband in the summer of 2006 without incident; and

(3) Ms. Nwoye eventually contacted the Nigerian security

services regarding Mr. Osuagwu’s criminal behavior.

60 F. Supp. 3d at 240.

 

Based on this evidence, the district court did not submit the

duress instruction as requested. The jury returned a verdict of

guilty. Then, as the district court noted, this court reviewed and

affirmed the district court’s decision.

In so doing, we

noted that Ms. Nwoye regularly left her home to attend

nursing school classes and to work at the hospital and was

thus “physically separated” from Osuagwu. [United States

v. Nwoye, 663 F.3d at 463.] She also met alone with Dr.

Iweala and did not tell him that she was being forced to
4

extort money from him. Id. Most importantly, the court of

appeals emphasized that “Osuagwu spent nearly two weeks

in California, thousands of miles away from Nwoye,”

giving her more than enough opportunity to notify law

enforcement. Id. at 463-64. “[A] defendant with such

‘countless opportunities to contact law enforcement

authorities or [to] escape the perceived threats’ cannot as a

matter of law avail herself of the duress defense.” Id. at

464 (quoting United States v. Scott, 901 F.2d 871, 874 (10th

Cir. 1990)).

Id. at 231. Further, with direct reference to Nwoye’s claim that

she may have suffered from BWS, we explained that 

Nwoye suggests the mere whiff of [BWS] arising from

these facts should alter the duress determination. . . . [But]

her theory is devoid of the other usual indicia supporting a

BWS defense—expert witnesses testifying to the effects of

isolation, financial dependence, or estrangement from

family members. Indeed, as discussed earlier, Nwoye had

many alternative sources of protections and support[,] . . .

[including] access to relatives, classmates, and teachers

with whom she could seek refuge. [Furthermore,] [s]he was

not under constant visual surveillance. The conspiracy in

which she participated lasted for months, . . . [and there

were] weeks in which Osuagwu was thousands of miles

away.

United States v. Nwoye, 663 F.3d at 465. 

So seeing, we affirmed. Years later came the present

petition for writ of coram nobis.

The petition originally came back to the trial judge. Due to

her having suffered serious injury, the matter was reassigned to
5

a different judge whose decision we now review. The district

court heard the testimony of four witnesses, including a forensic

psychologist, the defendant herself, trial counsel, and the public

defender now representing Ms. Nwoye. 

With the trial record and the testimony of the four witnesses

before him, the district judge applied the two-step analysis from

Strickland, 466 U.S. at 687-88, and correctly noted that “[t]he

Strickland prejudice prong requires only a reasonable

probability—that is, ‘a probability sufficient to undermine

confidence in the outcome.’” 60 F. Supp. 3d at 234 (quoting

Strickland, 466 U.S. at 694).

The district judge then explained that “‘the [duress]

standard is . . . partially objective; the defense is not established

simply by the fact that the defendant was coerced; he must have

been coerced in circumstances under which a person of

reasonable firmness in his situation would likewise have been

unable to resist.’” Id. at 238 n.6 (quoting Model Penal Code

§ 2.09, Explanatory Note (2001)) (emphasis added by the

district court).

Applying these standards, the district court reasoned:

In the context of duress, this means that a judge must

instruct a jury on the defense of duress only when the

defendant presents at least some evidence on both of the

necessary elements of the defense. “To prevail on a duress

defense, a defendant must convince the jury that (1) she

acted under the threat of immediate death or serious bodily

injury, and (2) that she had no reasonable legal alternative

to committing the crime, i.e., no chance both to refuse to do

the criminal act and also to avoid the threatened harm.”

Id. at 239 (quoting United States v. Nwoye, 663 F.3d at 467
6

(Tatel, J., dissenting) (other internal quotation marks omitted)).

With that and further reasoning, the court concluded, in my

view reasonably, that “[b]ecause no amount of expert testimony

could rectify [the] evidentiary deficiency, . . . there was no

prejudice to the defendant by virtue of her lawyer’s failure to

offer expert testimony on BWS for presentation to” the trial

court. Id. at 241. “Rather, in order for the defendant to be

entitled to a duress instruction, she must adduce evidence at trial

showing that she herself in fact had no reasonable legal

alternative.” Id. (citations omitted).

As did the district court, I recognize, as the majority points

out, that this court in the direct appeal noted the lack of expert

testimony on battered woman syndrome. Maj. Op. at 7, 11. 

However, I am not sure that I share my colleagues’ conviction

that the prior opinion “stressed” that omission, but rather listed

it among a series of facts. Id. at 7. I finally suggest that we

should remember what we are reviewing. The determination of

probabilities of the effect of counterfactual circumstances

partakes more of a decision of fact than of law. It is hornbook

learning that we review factual decisions of district courts with

deference. See generally Anderson v. City of Bessemer City,

NC, 470 U.S. 564 (1985). Indeed, Rule 52(a)(6) of the Federal

Rules of Civil Procedure provides that “[f]indings of fact . . .

must not be set aside unless clearly erroneous, and the reviewing

court must give due regard to the trial court’s opportunity to

judge the witnesses’ credibility.” While we may not be literally

reviewing “a finding,” we are essentially reviewing a factual

determination. In this case two district judges have had the

benefit of the credibility of witnesses and the experience of

making factual determinations. I would afford them that same

deference.

I therefore respectfully dissent.