                 FOR PUBLICATION
 UNITED STATES COURT OF APPEALS
      FOR THE NINTH CIRCUIT

UNITED STATES OF AMERICA,             
                Plaintiff-Appellee,          No. 10-30348
               v.
                                              D.C. No.
                                          3:09-cr-00120-BR-1
ALEXANDER LUKASHOV, Jr., AKA
Aleksandr Lukashov, Jr.,                       OPINION
             Defendant-Appellant.
                                      
       Appeal from the United States District Court
                for the District of Oregon
        Anna J. Brown, District Judge, Presiding

                  Argued and Submitted
          February 6, 2012—Seattle, Washington

                 Filed September 18, 2012

    Before: Mary M. Schroeder, Arthur L. Alarcón, and
            Ronald M. Gould, Circuit Judges.

                 Opinion by Judge Gould




                           11405
                 UNITED STATES v. LUKASHOV            11409


                        COUNSEL

Per C. Olsen, Hoevet, Boise & Olsen, P.C., Portland, Oregon,
for the defendant-appellant.

Kelly A. Zusman, United States Attorney’s Office, Portland,
Oregon, for the plaintiff-appellee.


                        OPINION

GOULD, Circuit Judge:

  Alexander Lukashov, Jr. appeals his jury conviction for
aggravated sexual abuse in violation of 18 U.S.C. § 2241(c).
We have jurisdiction under 28 U.S.C. § 1291, and affirm.

                             I

                             A

   In February 2009, Alexander Lukashov, Jr., who worked as
a long-haul truck driver in Portland, Oregon, was in a rela-
11410            UNITED STATES v. LUKASHOV
tionship with Cassedy Filer (“Cassedy”). Lukashov and
Cassedy lived together with their two young children and
Cassedy’s son and daughter from a previous marriage, J.F.
and T.F. Her son J.F. was then six years old, and her daughter
T.F. was eight. Before Lukashov’s departure on a long-haul
trip to New York, Cassedy asked him to take J.F. to her rela-
tives in Montana and to take T.F. along on the trip. Lukashov
agreed, and he, J.F., and T.F. left Portland on February 5.
Lukashov picked up a load in Washington, dropped J.F. off
in Montana, and proceeded, with T.F. in his truck, to take his
cargo to New York. He drove east to New York and delivered
the Washington load there. He picked up another load in New
York for delivery in Nevada. He then drove west with T.F.
and delivered the New York load in Nevada. There he picked
up still another load, destined for Portland. From Nevada, he
drove west and north, and returned to Portland with T.F. on
February 18.

   From the evidence introduced at trial, we see that Lukashov
was doing more than just driving his long-haul truck with T.F.
after he dropped J.F. off in Montana. Once returned to her
home and mother, T.F. told a tale of serial sexual abuse by
Lukashov as she traversed the country with him in his truck.

   Once Lukashov and T.F. had returned to her home, after
Lukashov had left the house, T.F. told her mother that
Lukashov had sexually abused her on the trip. T.F. described
the abuse and showed her mother bruises that she said
Lukashov had given her. When, a few days after T.F.’s return,
the police came to the house to arrest Cassedy on an outstand-
ing warrant, Cassedy reported the sexual abuse, and a police
officer spoke to T.F. The police took a pair of T.F.’s under-
wear and a pink blanket from the trip as potential evidence,
and arrested Cassedy.

   Cassedy’s sister, Katie White, took T.F. to CARES North-
west (“CARES”) for an examination. CARES is a medical
clinic that specializes in child abuse and is part of a multi-
                  UNITED STATES v. LUKASHOV              11411
disciplinary child abuse team that is overseen by the district
attorney’s office. Dr. Linda Lorenz is a pediatrician who eval-
uates children for abuse and neglect at CARES. To evaluate
a child, Lorenz does a medical examination and is assisted by
an interviewer to gain more information pertinent to the
child’s diagnosis and treatment.

   Together, Dr. Lorenz and Rachel Petke, a social worker at
CARES, evaluated T.F. Lorenz conducted a physical exami-
nation of T.F. T.F.’s genital exam and anal exam were nor-
mal, but Lorenz found “abnormal” bruises on the inside of
one knee and on the side of T.F.’s left hip. Lorenz asked T.F.
why her aunt had brought her to CARES. T.F. said that she
had gone on a trip with her “dad” and J.F. and that on the trip
Lukashov had anally penetrated her and had tried to vaginally
penetrate her but “couldn’t.” T.F. described the abuse to
Lorenz in the language of an eight-year-old, saying, for exam-
ple, that Lukashov had put his “private part” in “the part
where the poop comes out” and that he had tried to put it in
her “crotch.” Lorenz also asked T.F. about the bruises on her
body. T.F. said that she got the bruise on her knee from
Lukashov after he made her take off her pants and underwear
and get on her hands and knees, and that she got the bruise
on her hip from Lukashov grabbing her hip and “going really
fast.” T.F. added that there had been a bruise on her other hip
that had faded.

   After the physical examination, Petke interviewed T.F. The
interview was videotaped, and Dr. Lorenz and a police officer
observed it through a mirror. T.F. gave Petke a more detailed
account of the sexual abuse than she gave Lorenz. T.F. said
that the abuse happened after J.F. was dropped off in Montana
and that it happened more than once, in Montana, North
Dakota, and Nevada. T.F. said that the abuse took place in the
semi-truck and in a hotel room in Nevada. T.F. told Petke, as
she had Lorenz, that Lukashov had anally penetrated her and
that he had tried unsuccessfully to vaginally penetrate her.
She also said that Lukashov had made her perform oral sex
11412             UNITED STATES v. LUKASHOV
on him and ejaculated in her mouth. T.F. gave age-appropriate
descriptions, saying, for example, that Lukashov had tried to
“shove it in [her] porcupine” and that when Lukashov put his
“private part” in her mouth, “white stuff” that tasted “[l]ike
foamy” had come out.

                               B

   Lukashov was charged with aggravated sexual abuse in
violation of 18 U.S.C. § 2241(c) (Count 1), travel with intent
to engage in illicit sexual contact in violation of 18 U.S.C.
§ 2423(b) (Count 2), and transportation with intent to engage
in criminal sexual activity in violation of 18 U.S.C. § 2423(a)
(Count 3). Lukashov pleaded not guilty.

   The district court ruled on several evidentiary matters
before trial. Lukashov had moved to exclude T.F.’s state-
ments to Dr. Lorenz and Rachel Petke at CARES, and the dis-
trict court denied this motion. Lukashov also had moved in
limine to admit evidence of prior acts of Cassedy Filer to
show that she had a pattern of making false allegations against
her partner in a relationship. The district court ruled that
Lukashov could offer opinion or reputation evidence of
Cassedy’s bad character for truthfulness but not evidence of
specific prior acts. The district court held a Daubert hearing
on the proposed testimony of Dr. Lorenz about characteristics
of child sex abuse victims, and then held that Lorenz could
testify about characteristics that she looks for in child sex
abuse victims and that T.F.’s physical examination and state-
ments during the CARES evaluation were consistent with her
allegations of sexual abuse.

  The trial by jury lasted five days, and resulted in
Lukashov’s conviction. T.F. testified at trial, and the district
court also admitted the video of her interview with Rachel
Petke, giving the jury two opportunities to hear T.F.’s version
of events. Dr. Lorenz described T.F.’s CARES evaluation,
explained that child victims of sexual abuse can have normal
                    UNITED STATES v. LUKASHOV                   11413
genital and anal exams several days after the abuse, and testi-
fied that her physical findings and observations of T.F. were
consistent with T.F.’s allegations of sexual abuse. Forensic
scientist Amy Wilson testified that she found spermatozoa on
fabric cuttings from the interior crotch and interior seat areas
of T.F.’s underwear given to the police, and that the DNA
profile of the spermatozoa matched Lukashov’s DNA profile.
No seminal fluid was found on the underwear, however, and
no spermatozoa or seminal fluid was found on the pink blan-
ket.

   Lukashov testified in his own defense, and denied any
abuse. An important part of Lukashov’s theory of defense was
his allegation that Cassedy had coached T.F. into making
false allegations against him because Cassedy wanted to gain
a tactical advantage in the pending breakup of their relation-
ship. Lukashov testified that after returning from the trip with
T.F., he told Cassedy more than once that their relationship
was over, that Cassedy asked him to come back, but that in
his mind, it was over.

   On the third day of trial, at the close of the government’s
case-in-chief, Lukashov moved for a judgment of acquittal on
the ground of improper venue. The parties disagreed about
whether venue was a fact issue for the jury or a question of
law for the court and whether venue existed under either or
both paragraphs of the applicable venue statute, 18 U.S.C.
§ 3237(a). The district court recognized our precedent that
normally it is not for the court to determine venue and that it
is error to not give a requested instruction on venue.1 The dis-
trict court denied Lukashov’s motion because it concluded
that the government’s evidence, if credited by the jury, was
sufficient to show venue under either paragraph of § 3237(a).
Because of the varying theories on which venue might be
based, the district court decided to submit venue to the jury
on each of the possible theories urged by the government, “in
  1
   See United States v. Casch, 448 F.3d 1115, 1117 (9th Cir. 2006).
11414             UNITED STATES v. LUKASHOV
an effort to minimize any need for the child victim to testify
again in any retrial ordered because of the venue issues.”

   Lukashov also moved for a judgment of acquittal for insuf-
ficient evidence of purpose on all three counts, and the district
court denied this motion as well.

  The district court instructed the jury on the elements of
each of the charged crimes, and gave the following instruction
on venue:

       In addition to its burden to prove every element of
    each of the Counts against the Defendant beyond a
    reasonable doubt, as I am about to instruct you, the
    government must also prove by a preponderance of
    the evidence:

         1.   that the offense began, continued, or
              was completed within the District of
              Oregon; and/or

         2.   that the offense involved a form of
              transportation across state lines from,
              through, or into the District of Oregon;
              and/or

         3.   that the offense involved transporting a
              person from, through, or into the Dis-
              trict of Oregon.

   The jury found Lukashov guilty on Count 1 and not guilty
on Count 2; it did not reach a verdict on Count 3. The jury
returned a special verdict finding that the government did not
prove by a preponderance of the evidence that the offense
charged in Count 1 (1) “began, continued, or was completed
within the District of Oregon,” but that the government never-
theless proved venue by a preponderance of the evidence
because the offense (2) “involved a form of transportation
                      UNITED STATES v. LUKASHOV                      11415
across state lines from, through, or into the District of Ore-
gon” and (3) “involved transporting a person from, through,
or into the District of Oregon.”

  Lukashov filed post-trial motions for judgment of acquittal
based on insufficient evidence of purpose and improper
venue. The district court denied both motions. On Lukashov’s
challenge to the sufficiency of the evidence, the district court
applied the traditional standard of Jackson v. Virginia, 443
U.S. 307, 319 (1979), and concluded that viewing the evi-
dence in the light most favorable to the government, which
had gained the jury’s verdict, the “purpose” element of aggra-
vated sexual abuse had been proved beyond a reasonable
doubt.

   With regard to venue, the district court first noted that
venue in a criminal case had to be shown by a preponderance
of the evidence. The district court then held that venue was
proper on two alternative grounds, based respectively on the
first and second paragraphs of 18 U.S.C. § 3237(a). We
address only the first paragraph of § 3237(a) and whether
Lukashov’s sexual abuse of T.F. was a continuing offense that
was begun, continued, or completed in the District of Oregon.2
On this the district court reasoned:

        In hindsight, the Court believes its venue instruc-
   2
     The district court held that venue was proper under the second para-
graph of § 3237(a) because the jury had found that the offense involved
interstate transportation from, through, or into the District of Oregon, sat-
isfying subparagraph (2) of the jury instruction on venue. In ruling on
Lukashov’s post-trial motions for judgment of acquittal, the district court
concluded that its instruction in subparagraph (3), based on an alternative
“interstate commerce” theory, that venue was proper if “the offense
involved transporting a person from, through, or into the District of Ore-
gon,” was error. The district court held that the jury’s affirmative finding
on this alternative theory should be disregarded. Because we resolve
Lukashov’s venue challenge based on the first paragraph of § 3237(a), we
do not reach these issues.
11416            UNITED STATES v. LUKASHOV
    tions to the jury did not give sufficient guidance
    about the alternate venue theories on which the gov-
    ernment was proceeding after these venue issue[s]
    arose during trial. As to Count 1, the Court likely
    should have instructed the jury that if it found
    Defendant guilty and thereby found as fact that
    Defendant crossed a state line with the intent to
    engage in the requisite sexual act with T.F. and that
    Defendant then knowingly engaged in that sexual act
    with T.F., then the offense was, as a matter of law,
    a “continuing offense” (under the first paragraph of
    § 3237(a)) because the offense was completed in the
    District of Oregon when Defendant returned this
    eight-year old victim to her home. When the jury
    found beyond a reasonable doubt the facts necessary
    to convict the Defendant on Count 1, the Court now
    concludes there were not any additional facts for the
    jury to find as to venue under United States v.
    Casch[, 448 F.3d at 1117] before the Court should
    have determined venue was established on this the-
    ory as a matter of law under United States v.
    [Angotti, 105 F.3d 539, 541 (9th Cir. 1997)] and
    United States v. Childs[, 5 F.3d 1328, 1331 (9th Cir.
    1993)]. In other words, when the government proved
    the substantive elements of Count 1 beyond a rea-
    sonable doubt, it necessarily proved by a preponder-
    ance of the evidence the factual predicate for a legal
    determination that Defendant’s ongoing sexual abuse
    of T.F. was a continuing offense because it began
    sometime after T.F.’s brother was left in Montana
    but before Defendant carried his commercial load to
    New York, continued specifically through Nevada
    during the trip back to Oregon, and ended when the
    Defendant completed the trip and returned this minor
    child who was in his physical custody and control to
    the District of Oregon. In addition, finding that
    venue in Oregon is proper under the first prong of
    § 3237(a) is consistent with general policy consider-
                  UNITED STATES v. LUKASHOV               11417
    ations behind venue provisions; i.e., conducting the
    trial in a place convenient to the parties and the wit-
    nesses, all of whom in this cases were from Oregon
    when the child victim was unable to pinpoint geo-
    graphically all of the places along the trip where
    Defendant abused her.

       Although the Court respects and understands the
    jury’s finding on this venue issue, the Court now
    concludes the issue as to the first prong [of]
    § 3237(a) became a question of law when the jury
    found Defendant guilty of Count 1. Thus, to the
    extent the Court has the authority to determine venue
    was established under the first prong of § 3237(a) as
    a matter of law at this post-verdict stage, it now
    does.

   The district court sentenced Lukashov to 30 years in cus-
tody and entered judgment. Lukashov timely appealed. He
raises issues on several evidentiary rulings, on the sufficiency
of the evidence to convict him of aggravated sexual abuse,
and on whether venue was proper in the District of Oregon.
We review the issues in this order because the admissibility
of evidence bears on the larger issue of the sufficiency of the
evidence, and because the sufficiency of the evidence on
Lukashov’s sexual abuse of T.F. relates to the venue issue of
whether that offense began, continued, or was completed in
Oregon.

                               II

  We first address the evidence issues. We review the district
court’s evidentiary rulings for abuse of discretion and its
underlying factual determinations for clear error. See United
States v. Shyrock, 342 F.3d 948, 981 (9th Cir. 2003).

  Lukashov challenges the district court’s admission of T.F.’s
videotaped interview with Rachel Petke, contending that
11418             UNITED STATES v. LUKASHOV
T.F.’s statements to Petke were not made for purposes of
medical diagnosis or treatment and should have been
excluded as inadmissible hearsay.

   Before trial, the district court held an evidentiary hearing
on the admissibility of T.F.’s statements to Dr. Lorenz and
Petke at CARES. At the hearing Lorenz explained that the
physical exam and interview “go hand-in-hand in generating
a medical diagnosis,” and Petke similarly said that the pur-
pose of the interview was “to gather information to be used
in determining the diagnosis that the physician makes and to
make treatment recommendations.” In addition, Lorenz testi-
fied that before she examined T.F., she told T.F. that CARES
was “a regular doctor’s office,” that she and Petke worked
together as a “team”—she was the “doctor” and Petke was the
“talking person,” and that together they were going to make
sure that T.F. was healthy. The district court found that T.F.’s
statements to Petke were made for purposes of medical diag-
nosis and treatment and admitted the video of T.F.’s interview
with Petke under Federal Rule of Evidence 803(4). See Fed.
R. Evid. 803(4)(A) (excepting from hearsay rule statements
that are “made for—and [are] reasonably pertinent to—
medical diagnosis or treatment”).

   Lukashov argues that the purpose of T.F.’s statements to
Petke was to build a case against him rather than to obtain
medical diagnosis or treatment. Lukashov relies upon, among
other things, the interview’s removal from the medical exami-
nation setting, the observation of the interview by a police
officer, and T.F.’s use of the word “evidence” during the
interview.

   [1] We are not persuaded that the district court’s finding
on the purpose of T.F.’s statements was clearly erroneous. See
Fed. R. Evid. 104(a); Shyrock, 342 F.3d at 981. Because
“[s]exual abuse involves more than physical injury,” in cases
such as this one statements “made for purpose[s] of physical
or non-physical treatment and diagnosis” may be admitted
                  UNITED STATES v. LUKASHOV                11419
under Rule 803(4). See Guam v. Ignacio, 10 F.3d 608, 613
(9th Cir. 1993) (internal quotation marks and citation omit-
ted). That T.F.’s interview with Petke was separate from her
physical exam with Dr. Lorenz is immaterial; what matters is
that, to T.F., Petke, and Lorenz, the interview took place for
the purpose of, and was reasonably pertinent to, medical diag-
nosis and treatment. See Fed. R. Evid. 803(4); Ignacio, 10
F.3d at 613 & n.3. The district court reasonably concluded (1)
that T.F. understood the “whole evaluation” to be part of “a
medical process, something that she was brought to partici-
pate in for purposes of determining her safety and to ensure
that she would be protected and would be treated if she
needed help,” and (2) that Petke and Lorenz viewed the two
parts of the process as “inextricably intertwined and part of
the same diagnostic undertaking.” The district court also rea-
sonably credited Petke’s and Lorenz’s testimony that the pres-
ence of law enforcement did not change the medical nature of
their evaluation of T.F. Finally, T.F.’s references to “evi-
dence” do not make the videotaped interview inadmissible,
because they were brief, not prompted or followed up on by
Petke, and tangential to T.F.’s description of the sexual abuse
for medical examination purposes.

   [2] The district court did not abuse its discretion in admit-
ting Petke’s interview of T.F. under Rule 803(4).

                              III

  Lukashov contends that the district court erred in admitting
Dr. Lorenz’s testimony that her observations of T.F. and
T.F.’s statements were consistent with T.F.’s allegations of
sexual abuse.

   [3] Federal Rule of Evidence 702 governs the admissibility
of expert opinion testimony. Rule 702 in broad language
requires that the testimony “help the trier of fact to understand
the evidence or to determine a fact in issue” and that the
expert be sufficiently qualified to give the opinion. Fed. R.
11420             UNITED STATES v. LUKASHOV
Evid. 702; Primiano v. Cook, 598 F.3d 558, 563 (9th Cir.
2010). Expert testimony should be excluded “if it concerns a
subject improper for expert testimony, for example, one that
invades the province of the jury.” United States v. Binder, 769
F.2d 595, 602 (9th Cir. 1985), overruled on other grounds by
United States v. Morales, 108 F.3d 1031, 1035 (9th Cir. 1997)
(en banc).

   The district court permitted Dr. Lorenz to testify about four
general characteristics that she looks for in determining
whether a child has been sexually abused: (1) spontaneous
detail, (2) sexual knowledge, (3) sensory detail, and (4) age-
appropriate language. In ruling this testimony admissible, the
district court explained that Lorenz could “provide the jury
with material that is beyond their general knowledge, specifi-
cally with respect to the idea that there are age-appropriate
behaviors and language, age-appropriate capacities concern-
ing knowledge around sex, that are significant to a pediatri-
cian in her role.” The district court also let Lorenz give her
opinion that T.F.’s medical exam and statements during the
evaluation were consistent with her allegations of sexual
abuse. The district court limited its ruling by cautioning that
Lorenz could “not be asked any question that call[ed] for her
to comment on either explicitly or implicitly the inherent
credibility of [T.F.] as a witness.”

   [4] Lukashov argues that Dr. Lorenz’s testimony improp-
erly bolstered T.F.’s credibility. He cites United States v.
Binder, in which we held that expert testimony that the child
victim-witnesses could distinguish fantasy from reality and
truth from falsehood improperly “bolster[ed] the children’s
story” and “usurp[ed] the jury’s fact-finding function.” 769
F.2d at 602. The government argues that Lorenz’s testimony
was not improper because it was helpful to the jury and con-
cerned general characteristics of child sex abuse victims
rather than the credibility of T.F. in particular. See United
States v. Hadley, 918 F.2d 848, 852-53 (9th Cir. 1990) (hold-
ing that expert testimony about characteristics of “a class of
                  UNITED STATES v. LUKASHOV                11421
victims generally” not improper bolstering (internal quotation
marks and citation omitted)); see also United States v. Big-
head, 128 F.3d 1329, 1330-31 (9th Cir. 1997) (per curiam);
United States v. Antone, 981 F.2d 1059, 1062 (9th Cir. 1992);
cf. Binder, 769 F.2d at 602 (holding testimony improper
because “experts testified that these particular children in this
particular case could be believed”). The government also
urges us to follow the Eighth Circuit’s approach in United
States v. Whitted, where the court held that an expert permis-
sibly “express[ed] his opinion that his medical findings were
consistent with [the child]’s claims of sexual abuse.” 11 F.3d
782, 786 (8th Cir. 1993); see also United States v. Charley,
189 F.3d 1251, 1265-65 (10th Cir. 1999) (concluding that dis-
trict court did not abuse its discretion in allowing doctor to
“ ‘summarize the medical evidence and express an opinion
that the evidence is consistent or inconsistent with the vic-
tim’s allegations of sexual abuse’ ” (quoting Whitted, 11 F.3d
at 785)).

   [5] In our view, the government has the better of this argu-
ment. We conclude that the district court did not abuse its dis-
cretion in allowing Dr. Lorenz to testify about the
characteristics that she looks for when assessing a child vic-
tim’s story of sexual abuse, and to opine that her evaluation
of T.F. was consistent with T.F.’s allegations of sexual abuse.
Lorenz’s testimony was helpful to the jury because some
jurors would not have a general understanding of an eight-
year-old’s sexual knowledge and vocabulary and the level of
sensory detail to look for in a child’s allegations of sexual
abuse. See Fed. R. Evid. 702(a). By giving her opinion that
her medical findings and observations were consistent with
T.F.’s allegations of sexual abuse, Lorenz permissibly applied
her expertise to aid the jury in understanding the evidence.
See Whitted, 11 F.3d at 786; Antone, 981 F.2d at 1062. Her
testimony was limited and did not invade the jury’s fact-
finding function, as she did not comment on T.F.’s credibility
or state a diagnosis to the jury. See Whitted, 11 F.3d at 786
11422              UNITED STATES v. LUKASHOV
(holding that doctor’s diagnosis of child sexual abuse “went
too far”).

                               IV

   [6] On another evidence ruling, Lukashov challenges the
district court’s admission of Katie White’s testimony that T.F.
had a truthful character. Federal Rule of Evidence 608(a)
states that a witness’s credibility may be supported by opinion
testimony about the witness’s character for truthfulness, but
that “evidence of truthful character is admissible only after
the witness’s character for truthfulness has been attacked.”
We have said that Rule 608(a) “permits rehabilitation after
indirect attacks on a witness’s general character for truthful-
ness” but “prohibits rehabilitation by character evidence of
truthfulness after direct attacks on a witness’s veracity in the
instant case.” United States v. Dring, 930 F.2d 687, 691 (9th
Cir. 1991). “It is for the trial court, exercising its discretion,
to determine whether given conduct constitutes a direct or
indirect attack on a witness’s character for truthfulness.” Id.

   [7] Lukashov contends that White’s opinion testimony on
T.F.’s truthful character was not admissible because T.F.’s
character for truthfulness had not been attacked. We disagree.
Lukashov’s defense stressed that T.F. was lying because her
mother told her to lie, that she not only lied on the witness
stand at trial, but had been lying from the beginning, to the
police and to Dr. Lorenz and to Rachel Petke. Lukashov did
not merely point out inconsistencies in T.F.’s trial testimony.
Rather, he focused his defense, from opening statement
through closing argument, on calling T.F. a liar. As it appears
to us, the defense argument carried “ ‘strong accusations of
misconduct and bad character’ ” of T.F., which the district
court thought in fairness permitted evidence of her good char-
acter and truthfulness. See id. at 692 (quoting McCormick on
Evidence); 1 McCormick on Evidence § 47 (6th ed. 2009)
(stating that the greater the number of inconsistencies brought
out in cross-examination, “the stronger is the inference that by
                      UNITED STATES v. LUKASHOV                      11423
character the witness is a liar, not simply a witness who has
told an isolated lie”). Though this evidence ruling presents a
close question, we hold that the district court did not abuse its
discretion when it responsively admitted White’s testimony
on T.F.’s truthful character.3

                                     V

   Lukashov’s final evidentiary contention is that the district
court improperly excluded evidence of Cassedy Filer’s
alleged prior acts. Lukashov alleged that Cassedy made false
allegations of assault against her ex-husband, Merlin Filer,
and then threatened to take their children to force him to plead
guilty, and that she tried to plant false memories in T.F. of
Merlin trying to drown her in the bathtub and burn her with
a cigarette. Lukashov sought to introduce evidence of these
acts to support his theory that Cassedy had coached T.F. into
making false allegations of sexual abuse against him.

   [8] The district court excluded this evidence under Federal
Rule of Evidence 404(b). Lukashov argues that he offered the
evidence for a permissible purpose, to show a “pattern” in
Cassedy’s conduct, of fabricating allegations against her part-
ner and involving her children in the allegations. But by intro-
ducing Cassedy’s past pattern of conduct, Lukashov would
have been asking the jury to engage in propensity reasoning
along these lines: Cassedy had engaged in prior bad acts by
using her children against Merlin in past disputes, so it was
likely that she was using T.F. against Lukashov in this case.
In our view, Rule 404(b) prohibits this sort of propensity evi-
dence, and Lukashov’s reasoning does not bring the prior bad
  3
    Moreover, even if there was error in admitting White’s testimony about
T.F.’s truthful character, we would consider it harmless in the context of
this case, in which there was direct testimony of T.F. at trial and by video,
direct testimony of Lukashov, physical evidence of bruises on T.F. and
spermatozoa matching Lukashov’s DNA profile on her underwear, and
expert testimony that T.F.’s medical exam and statements were consistent
with her allegations of sexual abuse.
11424              UNITED STATES v. LUKASHOV
acts evidence within any of the uses permitted by Rule 404(b)
for prior bad acts evidence, “such as motive, opportunity,
intent, preparation, plan, knowledge, identity, absence of mis-
take, or lack of accident.” In any event, even if the matter is
fairly arguable, the district court’s excluding this evidence of
Cassedy’s past conduct related to Merlin Filer was not an
abuse of discretion.

                               VI

   We next turn to Lukashov’s challenge to the sufficiency of
the evidence. In reviewing a challenge to the sufficiency of
the evidence to support a verdict in a criminal case, we ask
“whether, after viewing the evidence in the light most favor-
able to the prosecution, any rational trier of fact could have
found the essential elements of the crime beyond a reasonable
doubt.” Jackson, 443 U.S. at 319. This standard is highly def-
erential because our criminal justice system gives primacy to
the role of the jury in determining guilt beyond a reasonable
doubt after being correctly instructed on the governing law.

   [9] Lukashov contends that the evidence at trial was insuf-
ficient because it did not establish that he had the requisite
purpose for conviction under 18 U.S.C. § 2241(c). His posi-
tion is that because his purpose in traveling to New York and
back to Oregon was to pick up and deliver goods in his capac-
ity as a long-haul truck driver, and because it was Cassedy
Filer’s rather than his idea for T.F. to go on the trip, no ratio-
nal juror could have found that his purpose in crossing a state
line was to engage in a sexual act with T.F. This contention
is without merit, and ignores the human ability and propensity
to act in light of multiple motives and purposes.

   The district court instructed the jury that to convict
Lukashov on Count 1, the government had to prove beyond
a reasonable doubt that he “traveled across a state line with
the intent to engage in a sexual act with T.F.,” and explained:
                   UNITED STATES v. LUKASHOV               11425
    [T]he government need not prove that the Defendant
    traveled across a state line for the sole and exclusive
    purpose of engaging in a sexual act. A person may
    have different purposes or motives for travel and
    each may prompt in varying degrees the act of mak-
    ing the journey. For purposes of [this element], the
    government must prove beyond a reasonable doubt
    that a dominant, significant, or motivating purpose
    of Defendant’s travel across a state line was to
    engage in a sexual act with T.F. In other words, the
    government must prove the sexual act was not
    merely incidental to the travel.

   [10] Viewed in the light most favorable to the government,
the evidence showed that Lukashov engaged in abhorrent sex-
ual acts with T.F. in three different states, Montana, North
Dakota, and Nevada. A rational jury could have found beyond
a reasonable doubt that once Lukashov formed the intent to
sexually abuse T.F., whether that occurred before he started
the trip or only after he dropped off J.F. in Montana and was
alone in his truck with T.F., he had that illicit intent for the
rest of the trip, until he returned her to her mother in Portland.
Given the repeated instances of abuse after the first time in
Montana, a jury could rationally infer that Lukashov crossed
the Montana-North Dakota and subsequent state lines with “a
dominant, significant, or motivating purpose” of committing
additional sexual acts. That Lukashov also had a commercial
purpose for crossing state lines does not negate the inference
that he had a significant or motivating purpose to continue
abusing T.F. because, as the district court correctly instructed
the jury, the government did not have to prove that sexually
abusing T.F. was the sole purpose of Lukashov’s interstate
travel. See United States v. Cryar, 232 F.3d 1318, 1324 (10th
Cir. 2000) (rejecting defendant’s insufficient evidence argu-
ment that “the dominant purpose of his crossing the state line
from Texas to Oklahoma was to earn a living, and not to com-
mit a sexual act”). It also does not matter that Cassedy rather
than Lukashov first suggested that T.F. go on the trip, so long
11426              UNITED STATES v. LUKASHOV
as Lukashov committed each element of § 2241(c) thereafter.
On the element of purpose, the Supreme Court’s standard in
Jackson v. Virginia was amply satisfied here. See 443 U.S. at
319.

                               VII

  We finally address Lukashov’s challenge to venue. We
review the district court’s determination on venue de novo.
United States v. Arango, 670 F.3d 988, 992 (9th Cir. 2012).

   [11] Proper venue is not a mere technicality. Instead, a
defendant in a criminal case has a constitutional right to be
tried in a district where the crime was committed. U.S. Const.
art. III, § 2, cl. 3 (“The Trial of all Crimes . . . shall be held
in the State where the said Crimes shall have been commit-
ted.”); id. amend. VI (“In all criminal prosecutions, the
accused shall enjoy the right to a speedy and public trial, by
an impartial jury of the State and district wherein the crime
shall have been committed . . . .”). This constitutional require-
ment is also implemented explicitly in the Federal Rules of
Criminal Procedure. See Fed. R. Crim. P. 18 (“Unless a stat-
ute or these rules permit otherwise, the government must
prosecute an offense in a district where the offense was com-
mitted.”).

  We have previously explained:

    Our venue law grows out of important concerns that
    a criminal jury trial be held near the place where the
    crime was committed and where prosecution can
    conveniently proceed. “In criminal cases venue
    involves important considerations of policy, with
    deep historical roots, that are now expressed in a
    complicated interplay of constitutional provisions,
    statutes and rules.” The Supreme Court has, at vari-
    ous times, expounded on the importance of prosecut-
    ing cases near the criminal defendant’s home. On
                   UNITED STATES v. LUKASHOV                  11427
     other occasions, the Court has stressed the impor-
     tance of a trial at the locus of the crime.

     ....

     Determining where an offense was committed, how-
     ever, has often been a sticky question. Many
     offenses, like complex conspiracies or transporting
     contraband, may continue through multiple venues.
     Congress has eased the burden of answering this
     question by providing [in 18 U.S.C. § 3237(a)] that
     continuing offenses may be prosecuted where they
     are begun, continued, or completed[.]

Angotti, 105 F.3d at 541-42 (citations omitted).

   The general rules controlling this sphere of law are well
settled: Venue is a question of fact that the government must
prove by a preponderance of the evidence. Casch, 448 F.3d
at 1117; United States v. Pace, 314 F.3d 344, 349 (9th Cir.
2002). In a jury trial, it is for the jury, not the court, “to deter-
mine that venue exists,” and “it is error for the court to
decline to give [an] instruction [on venue],” if properly
requested. Casch, 448 F.3d at 1117. The sufficiency of the
evidence to justify a finding on venue, by contrast, is a ques-
tion of law for the court. See 2 Charles Alan Wright et al.,
Federal Practice & Procedure § 307 (4th ed. 2011); see also
Angotti, 105 F.3d at 541.

   [12] On the other hand, the unusual circumstances of this
case, where the district court first gave an instruction on
venue and then, after the jury’s determination of guilt beyond
a reasonable doubt in substance, decided the venue question
of when the crime was completed as a matter of law, require
us to take a fresh look at the governing principles. We have
found no prior precedent holding that the evidence in a case
permitted the trial court, as the district court did here, to take
the venue issue from the jury and determine it as a matter of
11428              UNITED STATES v. LUKASHOV
law. However, we formulate the following rule to be applied:
Where a rational jury could not fail to conclude that a prepon-
derance of the evidence establishes venue, then a court is jus-
tified in determining venue as a matter of law. Precedent
supports the idea that when a court has failed to give a venue
instruction to the jury, that error will be viewed as harmless
if the evidence viewed rationally by a jury could only support
a conclusion that venue existed. E.g., United States v. Miller,
111 F.3d 747, 751-53 (10th Cir. 1997); see also Casch, 448
F.3d at 1117-18; United States v. Massa, 686 F.2d 526, 531
(7th Cir. 1982). It follows logically that, having given a venue
instruction, as the district court did here, if the evidence could
only be viewed by a rational jury as sustaining venue by a
preponderance of the evidence, which the district court con-
cluded was the case once the jury found the elements of 18
U.S.C. § 2241(c) beyond a reasonable doubt, then a court can
take the venue issue from the jury and decide it as a matter
of law.

   To decide whether venue is proper in a district, we “must
initially identify the conduct constituting the offense (the
nature of the crime) and then discern the location of the com-
mission of the criminal acts.” United States v. Rodriguez-
Moreno, 526 U.S. 275, 279 (1999). “To determine the ‘nature
of the crime,’ we look to the ‘essential conduct elements’ of
the offense.” Pace, 314 F.3d at 349 (quoting Rodriguez-
Moreno, 526 U.S. at 280). For continuing offenses, 18 U.S.C.
§ 3237(a) states:

    Except as otherwise expressly provided by enact-
    ment of Congress, any offense against the United
    States begun in one district and completed in
    another, or committed in more than one district, may
    be inquired of and prosecuted in any district in
    which such offense was begun, continued, or com-
    pleted.

    Any offense involving the use of the mails, transpor-
    tation in interstate or foreign commerce, or the
                  UNITED STATES v. LUKASHOV                11429
    importation of an object or person into the United
    States is a continuing offense and, except as other-
    wise expressly provided by enactment of Congress,
    may be inquired of and prosecuted in any district
    from, through, or into which such commerce, mail
    matter, or imported object or person moves.

   [13] Under Rodriguez-Moreno and § 3237(a), venue for a
continuing offense is proper if an “essential conduct element”
of the offense begins in, continues into, or is completed in the
charging district. 18 U.S.C. § 3237(a); Rodriguez-Moreno,
526 U.S. at 280; United States v. Stinson, 647 F.3d 1196,
1204 (9th Cir. 2011). Because Lukashov was convicted of
aggravated sexual abuse in violation of 18 U.S.C. § 2241(c),
we identify the “essential conduct elements” of aggravated
sexual abuse. See Rodriguez-Moreno, 526 U.S. at 279-80.
Section 2241(c) states:

    Whoever crosses a State line with intent to engage in
    a sexual act with a person who has not attained the
    age of 12 years, . . . knowingly engages in a sexual
    act with another person who has not attained the age
    of 12 years, . . . or attempts to do so, shall be fined
    under this title and imprisoned for not less than 30
    years or for life.

   [14] The essential conduct elements are (1) crossing a state
line, (2) with intent to engage in a sexual act with a child, and
(3) engaging in or attempting to engage in a sexual act with
a child. See Cryar, 232 F.3d at 1322. Given the continuing
nature of these elements, the district court correctly held, and
the parties do not dispute, that aggravated sexual abuse is a
continuing offense for purposes of 18 U.S.C. § 3237(a). See
id.

   We next “discern the location of the commission of the
criminal acts.” Rodriguez-Moreno, 526 U.S. at 279. On this
issue, the parties disagree. As we explained above, the district
11430              UNITED STATES v. LUKASHOV
court held, notwithstanding the jury’s finding that the offense
in Count 1 did not begin, continue, or end in the District of
Oregon, that venue was proper under the first paragraph of
§ 3237(a). The district court reasoned that once the jury found
that the government had proved the substantive elements of
Count 1 beyond a reasonable doubt, the government had nec-
essarily proved by a preponderance of the evidence that
Lukashov’s sexual abuse of T.F. was a continuing offense that
started after her brother J.F. was left in Montana, continued
as Lukashov drove to New York and back through Nevada,
and ended when Lukashov returned T.F. to her home in Port-
land, Oregon. The district court thus concluded that when the
jury found Lukashov guilty on Count 1, venue became a ques-
tion of law and the government had proved venue “as a matter
of law.”

   Lukashov contends that we must accept the jury’s finding
that the offense of aggravated sexual abuse did not begin,
continue, or end in the District of Oregon. He argues that
venue was not proper under the first paragraph of § 3237(a)
because no “essential conduct element” of aggravated sexual
abuse began, continued, or was completed in the District of
Oregon. See Rodriguez-Moreno, 526 U.S. at 280.

   We have previously said that a continuing offense “does
not terminate merely because all of the elements are met.”
United States v. Lopez, 484 F.3d 1186, 1192 (9th Cir. 2007)
(en banc). It is committed “over the whole area through which
force propelled by an offender operates.” United States v.
Johnson, 323 U.S. 273, 275 (1944).

   [15] Whenever precisely Lukashov formed his intent to
abuse T.F., crossed a state line with illicit intent to abuse her,
and abused her, there is no question here about his having
committed the offense during his abuse in Montana or North
Dakota. But what is important to our analysis is that the con-
tinuing offense did not terminate there. See Lopez, 484 F.3d
at 1192. Lukashov’s serial sexual abuse of T.F. continued
                   UNITED STATES v. LUKASHOV               11431
across the country to New York and back through Nevada to
Oregon. There can be no doubt that T.F., an eight-year-old
girl far from home in the custody of a man she called her
“dad,” was in fear of continued abuse and under constant
threat that the abuse would resume until reaching her home.
Even if Lukashov did not physically abuse T.F. after crossing
into Oregon, we conclude that at a minimum the significant
element of the crime of illicit intent while crossing a state line
continued in Oregon en route to her home. No evidence was
presented on Lukashov’s intent to support a finding to the
contrary. The evil intent and consequences of the crime neces-
sarily continued into Oregon. We hold that this continuing
offense of sexual abuse of a minor continued until T.F. was
safely home. Cf. Rodriguez-Moreno, 526 U.S. at 281 (“A kid-
naping, once begun, does not end until the victim is free.”);
Lopez, 484 F.3d at 1188 (holding that “a ‘brings to’ offense
under [8 U.S.C.] § 1324(a)(2) terminates when the initial
transporter drops the aliens off at a location in the United
States”).

  The district court correctly perceived that once the jury
found beyond a reasonable doubt that Lukashov had sexually
abused T.F. on the trip to New York and back to Portland, the
government had “necessarily” proved venue by a preponder-
ance of the evidence because the offense continued into and
was completed in Oregon as a matter of law. No rational jury
could have failed to so conclude.

   [16] We hold that venue was proper under the first para-
graph of § 3237(a) and need not address the district court’s
alternative holding based on the second paragraph of
§ 3237(a).

  AFFIRMED.
