In the
 United States Court of Appeals
              For the Seventh Circuit
                         ____________

No. 06-1820
UNITED STATES OF AMERICA,
                                               Plaintiff-Appellee,
                                v.

EDDIE LEE,
                                           Defendant-Appellant.
                         ____________
           Appeal from the United States District Court
      for the Northern District of Illinois, Western Division.
          No. 04 CR 50048—Philip G. Reinhard, Judge.
                         ____________
ARGUED FEBRUARY 9, 2007—DECIDED SEPTEMBER 17, 2007
                   ____________


  Before BAUER, FLAUM, and WILLIAMS, Circuit Judges.
  BAUER, Circuit Judge. A jury found Eddie Lee guilty
of possessing a firearm as a felon in violation of 18 U.S.C.
§ 922(g)(1). The district court sentenced Lee to 120 months’
imprisonment. On appeal, Lee argues that his convic-
tion should be overturned because the district court erred
in making several evidentiary rulings. He also argues that
18 U.S.C. § 922(g)(1) exceeds the scope of Congress’
authority under the Commerce Clause. For the following
reasons, we affirm Lee’s conviction.
2                                             No. 06-1820

                    I. Background
  On April 18, 2004, the Rockford Police Department
received a report that multiple gunshots had been fired in
the area of Garfield and Winnebago Streets at approxi-
mately 9:00 p.m. and that a white Ford Taurus was
involved. Officers Michael Garnhart and Amado Soria
were on patrol at approximately 2:23 a.m. on April 19,
2004 when they received a radio transmission stating
that gunshots had been fired in their immediate vicinity
and that a white Ford Taurus was involved. A few minutes
later, they saw a white Ford Taurus and followed it
until it pulled into a residential driveway at 622 Avon
Street.
  When the officers activated the police vehicle’s over-
head emergency lights, the driver of the Taurus, later
identified as Corey Francis, got out of the Taurus with a
black gun in his hand and fled. Officer Soria chased
Francis behind the residence. Lee got out of the passenger
side of the Taurus, and Officer Garnhart ordered him to
stop. When Lee turned around, Officer Garnhart saw him
holding a white “do-rag,” a cloth head-covering, in one of
his hands. Officer Garnhart ordered Lee to step forward
and lie on the ground. Lee complied, lying face down on the
ground between the sidewalk and the street. As Lee was
on the ground, Officer Garnhart received a radio call from
Officer Soria, who said that Francis had dropped his
handgun while running behind the residence. Officer Soria
recovered the gun dropped by Francis.
  Meanwhile Officer Garnhart saw Francis running
from behind the house and placed Lee in handcuffs
and locked him in the back of the police vehicle. Officer
Garnhart then pursued Francis on foot.
  Rockford Police Officer Melissa Sundly had heard the
traffic stop on her police radio when Officers Garnhart
and Soria initially pulled behind the Ford Taurus at
No. 06-1820                                               3

622 Avon Street. She arrived at 622 Avon Street a few
minutes after the other officers and secured the Taurus,
making sure that there was no one hiding in the vehicle
and that there were no weapons in view. She found a spent
shell casing in the passenger compartment of the vehicle
but no weapons. Approximately five minutes after she had
arrived at the scene, she observed two women come out
of the residence at 622 Avon Street. She also observed
a white do-rag on the ground near the Ford Taurus but
did not notice any firearm under the do-rag.
  Officer Garnhart apprehended Francis with the help of
other officers and returned to 622 Avon Street approxi-
mately five minutes after locking Lee in the police vehicle.
As Officer Garnhart reached down to retrieve Lee’s
white do-rag, he observed a handgun on the ground
partially covered by the do-rag. The gun and do-rag were
in the same location where he had earlier ordered Lee
to lie face down on the ground. Officer Garnhart had not
searched Lee or the surrounding area prior to placing
him in the police vehicle and pursuing Francis.
  After seeing the handgun underneath the do-rag, Officer
Garnhart took photographs of the gun and do-rag. Officer
Soria then picked up the gun, a Llama .32 caliber pistol,
and removed its ammunition. Officers Garnhart and
Soria searched Lee and took him to Winnebago County
Jail.
  At trial, the parties stipulated that Lee had been con-
victed of a prior felony. In addition to the testimony of
Officers Garnhart, Sundly, and Soria, the government
presented the testimony of Special Agent John Richardson,
an expert in the interstate nexus of firearms, who testi-
fied that the handgun recovered from beneath the do-rag
had been manufactured in Spain and therefore had
traveled in interstate and foreign commerce prior to its
recovery in Illinois. The government presented evidence
4                                               No. 06-1820

that there was gunshot residue on the cuff of the denim
jacket that Lee was wearing at the time of his arrest. The
government also presented the testimony of a fingerprint
expert, who testified that a partial fingerprint found on the
handgun was not Francis’ print but could be Lee’s, the
police officers who had handled the gun, or millions
of other individuals who possess similar fingerprint
characteristics.
  The government also called Nisheikia Foat to testify. She
resided at 622 Avon Street and was pregnant with Lee’s
child on the morning of Lee’s arrest. Foat testified that
she walked out of her residence when the police officer
had Lee on the ground. She testified that she did not
see any other individuals approach the area where the
gun was recovered from the time Lee was placed in the
police vehicle until the time Officer Garnhart recovered
the gun. Contrary to the officer’s testimony, she testified
that it took about an hour from the time she went out-
side until she saw the police officer pick up the do-rag.
  Foat also testified that she had received a letter from
Lee in the summer of 2004. In the letter, Lee asked Foat
to find witnesses to testify falsely that they had seen an
individual other than Lee run by and throw a gun on the
ground in the same location where the officers had recov-
ered the gun.
  Lee’s defense at trial was essentially that the recovered
handgun did not belong to him and that he was at the
wrong place at the wrong time on the morning of his
arrest. He claimed that he had met Francis just a few
minutes prior to his arrest and that he had been with
other people the entire day. He explained to the jury that
he was at a friend’s house at approximately 2:30 a.m.
when he asked some women that he knew to ask Francis
to give him a ride home. Lee said that Francis agreed and,
that as they approached Avon Street in Francis’ white
Ford Taurus, they saw a police van. Lee testified that
No. 06-1820                                                5

after seeing the police, Francis started “acting panicky”
and kept saying that he was ready to “high speed chase.”
Lee said that he then told Francis that he wanted to get
out of the car and to pull into the driveway at 622 Avon
Street. Lee testified that after Francis pulled into the
driveway, jumped out of the vehicle, and took off running,
he got out of the vehicle and obeyed the officer’s instruc-
tions: he lay down on his stomach with his hands ex-
tended in front of him. Lee denied that he was holding a
do-rag in his hands and denied that he had a gun when he
got out of the Taurus.
  The jury did not believe Lee’s story; they found him
guilty of being a felon in possession of a firearm, and he
was sentenced to 120 months’ imprisonment on March 9,
2006. This timely appeal followed.


                     II. Discussion
  On appeal, Lee argues that the district court abused it
discretion by (1) barring testimony regarding two shooting
incidents that occurred prior to his arrest; (2) permitting
testimony from the government’s gunshot residue expert
when the government failed to maintain a chain of custody
to protect Lee’s jacket from contamination; (3) barring
his witness from testifying as a gunshot residue or finger-
print expert; (4) permitting testimony from the govern-
ment’s fingerprint expert; and (5) limiting the cross-
examination of the government’s fingerprint expert. He
also argues that there is no sufficient nexus between the
charged offense and interstate commerce. We will ad-
dress each issue in turn.


  A. Relevancy of the Prior Shootings
  Lee first argues that the district court erred in excluding
testimony from witnesses about shootings that occurred
6                                            No. 06-1820

prior to his arrest. At trial, Officers Garnhart and Soria
informed the jury that they stopped the Ford Taurus on
the morning of Lee’s arrest because they had received a
radio transmission to stop the vehicle for unrelated
reasons. The district court found that the evidence of the
two prior shootings was not relevant to why the car was
stopped and would not make the existence of any fact of
consequence more or less probable. We review rulings on
the admissibility of evidence for abuse of discretion;
further, even if the district court made a mistake, we
will not reverse if the error was harmless. United States
v. Holt, 

, 936 (7th Cir. 2006).
  Evidence is relevant if it has “any tendency to make the
existence of any fact that is of consequence to the deter-
mination of the action more probable or less probable than
it would be without the evidence.” Fed. R. Evid. 401.
Relevant evidence “may be excluded if its probative value
is substantially outweighed by the danger of unfair
prejudice, confusion of the issues, waste of time, or mis-
leading the jury. . . .” Fed. R. Evid. 403.
  Lee contends that evidence that a white Ford Taurus
was involved in one or more shootings on April 18 and 19,
but that he was not present or involved in any such
shootings, would make it less probable that Lee possessed
a gun, fired a gun, or was present when a gun was fired on
the morning of his arrest. Lee is correct. However, the
testimony from the victims of the shootings would not
establish that Lee was not involved. The most that Lee
could establish was that none of the victims of the shoot-
ings implicated him in the shooting. We agree with the
district court that the evidence of the prior shootings
was not relevant to whether Lee possessed a firearm at
the time that he got out of the Taurus and was ap-
proached by Officer Garnhart.
  Lee also contends that evidence that the Taurus had
been involved in prior shootings would make it more
No. 06-1820                                              7

probable that any gunshot residue found on his jacket
came from inside the Taurus and not while he was pos-
sessing a gun. Maybe. Evidence that the Ford Taurus had
been involved in prior shootings would be relevant to
establish that there may have been gunshot residue in the
interior of the vehicle, which would help explain how
Lee’s jacket could have contacted gunshot residue with-
out Lee possessing or firing a handgun.
  Nevertheless, any error was harmless. Indeed, Lee was
able to offer several explanations as to why he had gun-
shot residue on his jacket, including the fact that residue
could have gotten on his jacket while he was in the
Taurus. During the cross-examination of Officers Sundly
and Soria, Lee’s attorney elicited testimony that the
officers found a spent shell casing in the Ford Taurus. The
government’s gunshot residue expert told the jury that
he could not state for certain that the defendant pos-
sessed or fired a firearm on the morning of his arrest. He
explained that residue could have transferred to Lee’s
jacket if it had contacted residue in the interior of the
Ford Taurus; if Lee had been standing in close proximity
to someone else when he/she fired a gun; if the jacket had
contacted residue in a clothing bag at the jail; or if the
handcuffs that the police officers used on him had previ-
ously been exposed to gunshot residue.
  Additionally, substantial evidence established Lee’s
guilt. Officer Garnhart testified that Lee got out of the
Taurus holding a white do-rag. The gun was found under-
neath the white do-rag in the same area where Lee had
been face down on the ground. Foat testified that she had
not seen any other individuals in the area where the
gun and do-rag had been recovered. Finally, Lee’s credibil-
ity was substantially impeached when he acknowledged
that he had asked Foat to locate one or two witnesses to
testify falsely that they saw an individual other than Lee
drop a gun in the area where he had been apprehended.
Considering the totality of the evidence against Lee, any
8                                              No. 06-1820

error in precluding evidence of the prior shootings was
harmless.


    B. Chain of Custody of Lee’s Jacket
  Lee next argues that the district court erred by admit-
ting Lee’s jacket. He contends that the testimony of the
government’s gunshot residue expert, Robert Berk,
regarding the gunshot residue found on the cuff of his
jacket was unreliable because the government failed to
protect the jacket from contamination by maintaining a
proper chain of custody.
  A district court’s evidentiary rulings concerning the
chain of custody for physical exhibits are reviewed for
abuse of discretion. United States v. Moore, 

,
1071 (7th Cir. 2005). “ ‘The standard for the admission of
exhibits into evidence is that there must be a showing
that the physical exhibit being offered is in substantially
the same condition as when the crime was committed.’”

(quoting United States v. Lott,

, 250 (7th Cir. 1988)). The government is
not required to prove a perfect chain of custody, as gaps
in the chain go to the weight of the evidence rather than
its admissibility. 

government need only show
that it took reasonable precautions to preserve the original
condition of the evidence, it does not have to exclude all
possibilities of tampering with the evidence . . . . [A]
presumption of regularity exists with respect to official
acts of public officers and, absent any evidence to the
contrary, the court presumes that their official duties
have been discharged properly.’ ” 

854
F.2d at 250).
  After Lee’s arrest, his jacket was placed into a cloth,
personal property bag at Winnebago County Jail with all
of his personal belongings. The personal property bags at
the jail are reused from one inmate to the next without
No. 06-1820                                              9

being sterilized or laundered between each use. Lee’s
jacket was removed from the personal property bag and
placed into a plastic bag. It is unknown who removed Lee’s
property from the cloth bag, but a Rockford Police Depart-
ment detective removed Lee’s property from the plastic
bag, inventoried the property, sealed the jacket in a
department evidence bag, and transferred the jacket to
the Illinois State Police to have it tested for gunshot
residue. Lee objected to the admission of the jacket,
arguing that the government had failed to take reason-
able precautions to preserve its original condition. He
argued that gunshot residue could have transferred from
the personal property bag to his jacket and that his
personal property should not have been transferred from
the cloth bag to the plastic bag.
  Lee’s arguments regarding the chain of custody and
potential contamination of his jacket go to the weight of
the evidence, not its admissibility. 

. The district court did not err in admitting the
evidence of Lee’s jacket. The court allowed Lee to argue
to the jury that they should place little weight on the
gunshot residue testimony due to the alleged lack of
proper chain of custody and the potential contamination
caused by the use of the “dirty” cloth bag to store his
jacket. Lee’s lawyer pointed out to the jury that on cross-
examination Berk had admitted that the gunshot residue
found on Lee’s jacket could have transferred to the jacket
after coming into contact with gunshot residue in the
personal property bag at the jail.


 C. Expert Witnesses
   1. Lee’s tendered Gunshot Residue and Finger-
      print Expert
  Lee next argues that the district court abused its
discretion by refusing to allow his tendered expert, Wayne
10                                            No. 06-1820

Hill, to testify as either a gunshot residue or fingerprint
expert. Hill has an associate degree in police science
and had worked as a law enforcement officer for 14 years.
After leaving law enforcement, he started his own busi-
ness that focused on homicide scene reconstruction.
  The admissibility of expert testimony is governed by
Federal Rule of Evidence 702, which establishes two
admissibility requirements for expert testimony: (1) the
expert must be qualified, and (2) the subject matter of the
expert’s testimony must consist of specialized knowledge
that will be helpful or essential to the trier of fact in
deciding the case. United States v. Lanzotti, 205F.3d 951,
956 (7th Cir. 2000). The district court has broad discre-
tion in determining the competency of a witness as an
expert. 

a district court’s decision to ad-
mit expert testimony for an abuse of discretion. United
States v. Young, 

, 656 (7th Cir. 2002).
  The district court determined that Hill lacked the
experience and training necessary to assist the jury in
understanding how gunshot residue can transfer from
one surface to another and how gunshot residue found
only on the right cuff of Lee’s jacket suggests that he
had not recently fired a gun. We agree. Hill testified that
he had never been asked to conduct testing for purposes
of ascertaining the properties or characteristics of gun-
shot residue and that he had neither the training nor
experience necessary to conduct the actual testing of an
object for the presence of gunshot residue.
   We also agree with the district court’s refusal to allow
Hill to testify that the partial fingerprint found on the
recovered gun was unsuitable for comparison. Hill was not
a qualified expert; he had no formalized training or
experience in the analysis of fingerprints. Hill admitted
during voir dire that he did not have the necessary experi-
ence to render an opinion as to whether the latent print
lifted from the handgun was suitable for comparison.
No. 06-1820                                                  11

  Because Hill was not qualified as either a gunshot
residue or fingerprint expert, the district court did not
err in barring his testimony.


    2. The Government’s Fingerprint Expert
  Lee next contends that the district court erred in allow-
ing the testimony of the government’s fingerprint expert,
Stephanie Bodine. The fingerprint on the handgun recov-
ered by the police was a partial fingerprint, suitable for
comparison but not for identification purposes. Bodine
testified that based on her comparison of the latent print
on the firearm with Francis’ fingerprints, she was able to
eliminate Francis as the individual who left the print on
the gun. After comparing the latent print to Lee’s finger-
print, Bodine was unable to exclude or identify Lee as
the individual who left the print on the gun. Lee argues
that Bodine’s testimony was irrelevant because it would
not demonstrate that it was more probable that Lee
possessed the gun.
  The district court disagreed and found Bodine’s testi-
mony relevant. The district court ruled that the govern-
ment could present evidence that the partial print was
suitable for comparison rather than identification pur-
poses, that Francis had been eliminated as the in-
dividual who left the print on the gun, and that Lee had
not. We agree with the district court that the fact that
Francis had been excluded as the individual who left the
partial fingerprint on the gun was relevant.1


1
  Lee also argues that the district court erred by refusing his
request that the police officers involved in the investigation
submit their fingerprints for analysis. We disagree. The finger-
print on the handgun recovered by the police was suitable for
                                                  (continued...)
12                                                No. 06-1820

  Lee next argues that the district court erred by pre-
cluding him from cross-examining Bodine concerning
the fact that she had asked six other scientists at her
laboratory to review the partial fingerprint from the
recovered gun and one of those analysts believed that the
partial print was not suitable for comparison. When Lee’s
counsel indicated to the court that he intended to cross-
examine Bodine on the fact that she had consulted with
the other fingerprint analysts, the government made a
hearsay objection, arguing that cross-examination on this
point would only be admissible if Bodine’s consultation
with the other analysts was part of the basis of her
opinion. We review district court rulings on hearsay
objections for an abuse of discretion. United States v.
Dumeisi, 

, 574 (7th Cir. 2005).
  Federal Rule of Evidence 705 provides that an “expert
may testify in terms of opinion or inference and give
reasons therefor without first testifying to the underlying
facts or data, unless the court requires otherwise. The
expert may in any event be required to disclose the
underlying facts or data on cross-examination.” The
bases of opinion testimony by experts is governed by
Federal Rule of Evidence 703, which in part provides:
     The facts or data in the particular case upon which an
     expert bases an opinion or inference may be those
     perceived by or made known to the expert at or before
     the hearing. If of a type reasonably relied upon by
     experts in the particular field in forming opinions or
     inferences upon the subject, the facts or data need not


1
  (...continued)
comparison but not for identification. Thus, comparing the
latent print on the gun to the officer’s fingerprints only could
have excluded the possibility that the print was left by one of
the officers, which would have been detrimental to Lee’s case.
No. 06-1820                                              13

    be admissible in evidence in order for the opinion or
    inference to be admitted.
  The district court conducted voir dire to determine
whether Lee could conduct cross-examination of Bodine
on this point. Bodine stated that after she concluded
that one of the latent prints on the firearm was suitable
for comparison, she asked six other analysts in her labora-
tory to review the print. She testified that she had consid-
ered the opinions of the six analysts in reaching her
conclusion that the print was suitable for comparison.
Here, the district court barred Lee from cross-examining
Bodine regarding the opinions she obtained from the
other fingerprint analysts. The court found that such
opinions were inadmissable hearsay:
    [I]n many cases the expert is relying on his or her
    own opinion, and that is proper. In some cases the
    expert relies on outside data that is used to form her
    conclusion. In this case [Bodine] is using the same
    data that these other experts in her same office use.
    There’s nothing new in terms of the evidence that
    this expert relied on. She is just confirming her own
    expert opinion by asking other experts to look over
    the same information and give her a confirming
    opinion or not.
    In my opinion that is not what is contemplated by
    admission of this evidence under Rule 703, and it
    is therefore hearsay, and I would deny cross-examina-
    tion . . . . And I say that because the government could
    in every case piggy back its own expert’s opinion by
    saying, well, we always have a second fingerprint
    expert look at it, as well, and that confirmed my
    examination.
  Bodine testified that she considered the opinions of the
other analysts but did not base her conclusion—that one
of the prints on the gun was suitable for comparison—on
14                                             No. 06-1820

the other analysts’ opinions. Rather, she confirmed her
conclusion. Although the call is close, we find that the
district court did not abuse its discretion in barring Lee
from cross-examining Bodine regarding the opinions of
the six analysts.
  At any rate, any harm from denying cross-examination
on this point was limited and does not warrant reversal.
Bodine explained to the jury that the partial fingerprint
left on the gun could have been left by Lee, the police
officers who had handled the gun, or millions of other
individuals with similar fingerprint characteristics.


  D. Interstate Commerce
  Finally, Lee argues that the charged offense did not
affect interstate commerce. In order to violate 18 U.S.C.
§ 922(g)(1), a defendant must have a prior felony convic-
tion, posses a firearm, and the firearm must have
traveled in interstate commerce prior to the defendant’s
possession of it. United States v. Ortiz, 

, 982
(7th Cir. 2007). Lee does not dispute Special Agent Richard-
son’s testimony that the firearm recovered from under-
neath the do-rag had been manufactured in Spain and
therefore had traveled in interstate and foreign commerce
prior to its recovery in Illinois. “Movement in interstate
commerce is all the Supreme Court requires under the
statute.” United States v. Jackson, 

, 492 (7th
Cir. 2007) (citing Scarborough v. United States, 

, 577, 

, 

(1977); United
States v. Williams, 

, 400 (7th Cir. 2005)).


                    III. Conclusion
  For the foregoing reasons, the judgment of the district
court is AFFIRMED.
No. 06-1820                                        15

A true Copy:
      Teste:

                   ________________________________
                   Clerk of the United States Court of
                     Appeals for the Seventh Circuit




               USCA-02-C-0072—9-17-07