5 September 2009
Summary of Gunshot Residue Evidence
The prosecution hired a lab to examine clothing seized from the home of the
defendant on October 21, 1997. The defendant had no criminal record, and
worked as a manager and investigator for 20 years. He was an avid hunter,
target shooter, and legally owned (1) handgun, (2) rifles, and (2) shotguns.
He had a concealed weapons permit from the Lancaster County Sheriff, for
personal protection. He had also shot and killed a 7 point buck whitetail
deer only two days before his initial arrest on December 4, 1996. The
clothing worn hunting and target shooting had been in a plastic bag with the
clothing seized by police, from December 2, 1996 to October 19, 1997.
At the trial, the prosecution expert reported finding particles he claimed
were unique to Gunshot Residue as follows: (6) particles on ballcap (no
specific area), (2) particles on left shirt sleeve, (1) particle on left
jeans leg, and (1) particle on left sneaker. He used Inorganic testing only,
SEM/EDX, to identify the lead, barium, antimony particulates (PbBaSb).
He did not use M.E.C.E. to identify the organic components of smokeless
gunpowder in the residues.
A defense gunshot expert was approved only (6) days before trial, but was
never consulted. He never testified.
In 2008, the defense obtained lab reports from the hired expert that impeach
his entire testimony and contrived experiment. The automated analyses also
list (1) unique GSR on the left sleeve (not 2) and (0) unique GSR
on the left jean leg (not 1).
Relevant Facts about Defendant's Clothing
- The defendant had worn the ballcap
fishing and target shooting many times. The shirt and jeans had been in the
bag of clothing used for hunting, and on October 20, 1997, for fishing.
- The State Police testified that they
did not wear gloves while handling the ballcap and shirt, but falsely
testified to wearing gloves while handling the jeans and sneakers.
- The State Police kept the
defendant's clothing in a patrol car trunk for (6) days before transporting
them to the hired lab several hours drive away.
- The prosecution expert
testified that the defendant's clothing showed no sign of laundering, since
the particles found were larger than 2 microns in size and not oxidized.
Possible Sources of Residues on Defendant's Clothing
- Accidental transfer from the hands
of Trooper Mowrey, who admitted at least to not wearing gloves when handling
the ballcap and shirt. Organic testing might confirm residues came from his
weapon, or weapon other than murder caliber.
- Intentional transfer from Trooper
Mowrey, very possible due to his rampant misconduct, again availed to
organic testing.
- Residual gunshot residues from
defendant's prior target shooting with .45 caliber Smith & Wesson handgun,
availed to organic testing.
- Residual gunshot residues from
defendant's prior target shooting or hunting with .270 caliber rifle, .22
caliber rifle, or 12 gauge shotgun, availed to organic testing.
- Residual gunshot residues from
handling broken shotgun shells the day prior to the murder, availed to
organic testing.
- Automobile Disc-Brake dust
transferred from defendant's car trunk, to fishing gear and boat motor and
batteries, and then to the clothing in question. The defendant had installed
new brakes on the car and left the old calipers, rotors, and brake pads in
the trunk. The Journal of Forensic Science reported in September 1998, that
such residues contain lead, barium, antimony (PbBaSb) particulates that are
identical to gunshot residues, and cannot be differentiated absent organic
testing.
Other Reasons Invalidating Clothing Analyses
- In 2006, a Capital Case in Bradford County involved clothing that might
have gunshot residue present. Another State Police expert testified: “The
State Police no longer perform gunshot residue testing on clothing, because
clothing contains different dyes which contain antimony and barium, and
since we do not know the background levels of these elements in clothing, we
cannot know if any antimony and barium particles found, existed from the
dyes, not gunshot residue.” (My paraphrasing).
Testimony of John Evans,
State Police Chemist Notes of Testimony, 27 January 2006, pages 1-21 Commonwealth v. Briggs, Bradford County, No. 348 CA 2004
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