FILED

UN[TED STATES DIS'I`RICT COURT  1 1 2014

FOR THE DISTRICT OF COLUMBIA

Cl&l'l¢, U.S. Ul$frit.‘f & Bank;u

Courts for the Dlstrir;t of Caluii'iiriia

UNITED STATES OF` AMER]CA

v. criminal No. 03-360 (Rcl.p

EVAN S. LIBERTY., and

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PAuL A. sLouGH, )
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DUST1N L. HEARD, )

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Defendants.
 

UNITED STATES OF AMERICA

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v. ) Criminal No. 14-107 [RCL)
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NICHOLAS A. SLATTEN, )

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Defendant.
 

MEMORANDUM OPINION
Bet`ore the Court is del`endants’ motion [4?2] to exclude the expert testimony of`
government expert Robert F. Mothershead ll . Upon consideration of the def`endants’ motion, the

government’s opposition [500],' oral argument held on May 29, 2014, the applicable law, and

the entire record herein, the Court will Dl`-.NY the motion to exclude Mothershead’s testimony.
l. BACKGROUND

Both the Distriet Court and the Court of Appeals for the District of Columbia Cireuit
have previously described the factual background of this case. Uni!ed Srates' v. Sfough, 677 l*`.
Supp. 2d 112, 116-129 (D.D.C. 20()9) ("Slough }"), vacared, 641 F.3d 544, 555 (D.C. Cir. 2011)

"Slough I}"); Slough 11’, 641 F.3d at 547-49. 'l`hus, the Court will now only highlight the

l The defendants apparently have opted not to submit a reply brief for this mo1ion.

relevant facts and procedural background.

According to evidence that defendants intend to introduce at trial, some unknown item
injured defendant Dustin Heard’s arm during the Nisur Square incident on September 16, 2001
Defs.’s Mot. at 2. At the time of this injury, defendant Heard was the rear turret gunner in one
vehicle; Jererny Ridgeway, who has pled guilty in this case, was the front turret gunner in that
same vehicle. Gov’t’s Opp. at 2. To Ridgeway, the object that injured Ileard appeared to be a
pen flare; Heard usually carried a pen flare on his person during missions. la’. Heard, however,
attributed his injury to a tracer round. id

The government acquired defendant Heard’s clothing from that day and sent it to FBI
forensic chemist Robext F. Mothershead ll for analysis. Id. at 3. Mr. Mothershead examined
defendant Heard’s glove, sleeve, and hood. Mot. at 3. Mr. Mothershead performed chemical
tests on the glove, sleeve, and hood. On the glove, he found barium and magnesium particles.
Id. at 2-3. Magnesium and barium are not elements normally found within or on clothing (Opp.
at 6); however, they do match some of the chemicals within a pen flare. Mot. at 3-4. Mr.
Mothershead performed no further tests-he did not attempt to establish that the barium and
magnesium on defendant Heard’s glove came from a pen flare, only that they could have come
from a pen flare. .S'ee Mot. at 3 ("[barium and magnesiurn] may be found in various other
chemical compositions and products" (emphasis rcmoved)). The govemment intends to call Mr.

Mothershead as an expert witness during trial. Defendants now seek to have his testimony

excluded

I1. LEGAL STANDARD

Admissibility of expert testimony is govemed by Rule 702 of the Federal Rules of

Evidencc ("Rule 702"). lt states that a witness who is
qualified as an expert  may testify  if:'

a) the expert’s scientif`tc, technical, or other specialized knowledge
will help the trier of fact to understand the evidence or to
determine a fact in issue;

b) the testimony is based on sufficient facts or data;

c) the testimony is the product of reliable principles and rnethods; and

d) the expert has reliably applied the principles and methods to the
facts of the case.

Fed. R. Evid. ?02.

The Supreme Court further refined this threshold test in Dauber! v. Merrell Dow
Pharmaceutfcals, Inc., where it held that admissible expert scientific testimony must be based on
"scientit`ic knowledge,"` and that it must "assist the trier of fact to understand the evidence or
determine a fact at issue"~a "condition [that] goes primarily to relevance" and can be met by "a
valid scientific connection to the pertinent inquiry." 509 U.S. 579, 589-90, 592 (1993).
"Pertinent evidence based on scientifically valid principles will satisfy those demands." Id. at
597. 'l` he Supreme Court also offered four nonexclusive, non-dispositive factors to guide trial
courts in their assessments of expert testimony: (l) whether the opinion at issue can be tested; (2)
whether it has been peer-reviewed; (3) the rate of known or potential error; and (4) general
acceptance within the scientific community. }d. at 593-94. These factors are neither exclusive
nor dispositive because "the inquiry envisioned by Rule ?02 is  a flexible one." Id. at 594.

As with any other piece of evidence this Court may exclude Mr. Mothershead’s
testimony if "its probative value is substantially outweighed by a danger of  unfair prejudice,

confusing the iSSues, misleading the jury, undue delay, wasting time, or needlessly presenting

cumulative eviclence." Fed. R. Evid. 403.

III. ANALYSIS

Defendants do not challenge Mr. Mothershead’s qualif`ications, and so the Court need not
consider them any further. They also do not contest that Mr. Mothershead’s tests produced
"‘scientific knowledge" to satisfy Dauber£. Dauberr, 509 U.S. at 589-90. Rather, the defense
challenges the probative value of his testimony. Essentially, the defense argues that, because Mr.
Mothershead only matched the chemicals against pen flares and not against anything else, the
contemplated evidence will not just fail to aid thejury but will in fact confuse it.

Daubert counsels that the district court should "focus  solely on principles and
methodology, not on the conclusions that they generate," Dauberr, 509 U.S. at 595. But here
defendants quibble primarily with Mr. Mothershead’s ultimate conclusion (see Mot. at 7 ("Mr.
Mothershead then qualified his conclusions to a degree that renders them effectively
meaningless")). This misplaces the proper inquiry under Dauberr_if defendants want to have
Mr. Mothershead’s testimony thrown out, they need to successfully challenge his process.

Defendants’ methodological challenge to Mr. Mothershead’s expected testimony
essentially comes down to a protest over how they think the government will choose to use it.
As far as the Court can tell, the defense does nol object to Mr. Mothershead testifying that he
found chemicals on l-Ieard’s glove that were consistent with the chemicals found within pen
flares', instcad, they object to using the testimony to prove anything else. In Ambros:'n:' v.
Labarraque, 101 l~`.3d 129 (1996), this Circuit confronted a similar issue. There, the plaintiffs
wanted to use a doctor’s testimony to prove a certain type of drug caused a birth defect, even
though the doctor had not ruled out other potential causes. See Ambrosini, 101 F.3d at 131-32.
The Court held that "the Dauberz analysis does not establish a heightened threshold for the

admission of expert evidence, but rather focuses on the court's "gatekeeper’ role as a check on

‘subjective belicf" and ‘unsupported speculation."’ fci at 134 (citing Dauber!, 509 U.S. at 590).
Mr. Mothershead’s testimony would fit neither of these categories; he tested both the i]are and
the glove and found similar chemicals, which is certainly not subjective or unsupported That
Mr. Mothershead did not establish that the chemicals on Heard’s glove specifically came from a
pen flare is irrelevant "Under Dauber!  evidence does not warrant exclusion simply because
it fails to establish the causal link to a specified degree of probability." Ambrosin:`, 101 F. 3d at
135.

As the government stated correctly in its brief, def`endants’ complaints about Mr.
Mothershead’s testimony go to its weight, not its admissibility See Opp. at 6-?. Dauber! and
the new Rule 702 did not make the rules on admitting expert testimony more restrictive; "the
rejection of` expert testimony is the exception rather than the rule." Fed. R. Evid. 702 advisory
committee’s note. Expert testimony should be excluded only when it is based on "guesswork,
Speculation, and conjecture." Joy v. Beh' He!icr)p!er Textron, !nc. 999 F.2d 549, 568 (D.C. Cir.
1993) (intemal quotation omitted). Mr. Mothershead’s testimony is not based on speculation.
Barium and magnesium were present both on Heard’s glove and in the pen flare. No one
disputes this. This Court cannot exclude expert testimony with such a foundation.

IV. CONCLUSION
For the foregoing reasons, the Court DENIES the defendants’ motion [4?2] to exclude

the expert testimony of government expert Robert F. Mothershead II.

A separate Order consistent with this Memorandum Opinion shall issue this date.

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Date ROY E C..LAMBERTH
United States District Judge

