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Articles
Colleagues and friends: For those of you that do not have
access to cable or DSL modems, these papers are available on CD in pdf format. Please contact bburnett@meixatech.com
if you would like a CD of these articles sent to you. Provide your full address in that email. A limited number
of CDs will be sent each month.
Documentation of the Discharge
of a .380 Pistol Within a Vehicle
2.1MB pdf file (approx 10 min @ 56k)
This case involves the alleged single discharge of a .380
pistol within a
vehicle and documenting the GSR burden on interior surfaces of a similar car resulting from such a discharge.
Examination of a 30+ Year-Old Shooting Death with a Ruger .44 Magnum Carbine That Has No Remaining Physical Evidence
1.08MB pdf file (approx 5 min @ 56k)
The victim sustained a fatal bullet to the head from a Ruger
.44 Magnum Carbine (18.5-inch barrel length) in 1973. The shooter was the victim’s husband who claimed the rifle
accidentally discharged while he was cleaning the newly-purchased rifle. At the time, the shooting was determined
to be accidental. No physical evidence remains of this shooting with only the autopsy report and a small number
of shooting scene photographs. In 2006, that same shooter was accused of the shooting death of his most recent
wife. The 1973 shooting was re-filed as murder. The characteristics of the Ruger .44 Magnum Carbine are examined
in this study as to partially-burned powder discharge from the muzzle as well as sooting of close targets.
Investigation of the shooting of
teenager Christopher St. Louis
3.5MB pdf file (approx 18 min @ 56k)
The shooting of teenager Christopher St. Louis by off-duty
police officer Tanaya Webb at the Santee, California Petco shopping center the evening of February 16, 2003 is
examined. Four shots were fired in one second with a Glock Model 27, .40 caliber pistol and St. Louis received
four wounds: left chest, right chest, lower right abdomen and right arm. He died minutes after being shot. St.
Louis was shot while running towards Webb. The shooting scene reconstruction indicates that St. Louis received
the first shot approximately 27 feet and the last shot when he was approximately 15 feet from Webb.
Investigation of the death
of Colonel James Sabow, USMC
5.08MB pdf file (approx 25 min @ 56k)
The investigation of the circumstances of the death of Colonel James E. Sabow
is continued in this report. The extraordinary quality of the photographs of the crime scene and autopsy was instrumental
for this examination. Evaluation of the gunshot residue, back spatter residue, cranial injuries, blood spatter,
the Colonel s bathrobe and the position of the body lead to the conclusion that Colonel James Sabow was murdered
and an attempt was made to stage the body to appear that he committed suicide. The Colonel was rendered unconscious
and mortally wounded by a devastating blow by a broad, flat club to the right occipital region of his skull prior
to the intraoral shotgun blast. The reconstruction of the homicide crime scene indicates that three or more assailants
were likely.
The Bizarre Case of People
v. Contreras
1.7 MB pdf file approx 7-10 mins @56k
The victim died from a single.22 bullet wound to the chest
that came through a window and the victim's girlfriend was accused of the homicide. This case has been published
(B.R.Burnett, Journal of Forensic Sciencses. 2001. 46(2):379-385). The purpose of this article is to reexamine
the extraordinary nature of the physical evidence of this case and discuss the testimony of three experts who testified
in one or more of the three trials of People v. Delia Contreras.
Lead in House and Automotive
Keys
1MB pdf file approx 5-7 mins @56k
Concentrations of lead in keys, both old and new are reported.
A health risk exists for the entire population, not only for locksmiths/key makers. Small children may have significant
lead exposure, especially for those children that put keys in their mouths.
Gunshot residue samplers from suspects in shooting cases should not be reported as having particles "consistent
with gunshot residue" when the only particles found are lead. A significant environmental source of lead particles
in gunshot residue samplers is likely from house and automotive keys.
The Gunshot Residue Evidence of People
v. Robert Blake: A Case of Forensic Alchemy
3MB pdf file approx 15-21 mins @56k
The gunshot residue evidence in the case of People v. Robert Blake is presented.
Automated scanning electron microscopes (SEM) equipped with elemental analyzers (energy dispersive X-ray spectroscopy,
EDS) were used to find and identify presumptive gunshot residue particles from the evidence. Errors were made in
the handling of Mr. Blake after the shooting, testing the murder weapon, testing Mr. Blake's revolver, storage
of Mr. Blake's clothing, interpretation of spectra from almost all of the analyses and the assignment of particles
as "consistent" or "highly specific" to gunshot residue. In addition, the gunshot residue reports
fail to distinguish between individual and populations of particles, a critical distinction considering virtually
all elemental combinations of lead, antimony and barium found in gunshot residue may also originate from environmental
sources. A limited evaluation of the testimony by the defense expert is presented. Mr. Steven Dowell of the Los
Angeles County Department of the Coroner provided a summary on this case at the Scanning 2005 meeting (April 7,
2005, Monterey, California). A transcript of Mr. Dowell's talk is attached to this article.
22 Rimfire Ammunition
7 KB pdf file (< 1 min @ 56k)
Antimony
Coats Many .22 Caliber Bullets
241 KB pdf file (approx.
2.5 mins @ 56k)
Macro Imaging
with a Digital Camera: Examination of a .22 Revolver
The Pixera 600CL, a 5.8 megapixel peltier cooled CCD camera,
when attached to a macro zoom lens can be stopped down > f 44. This allows for extraordinary depth of field
of objects up to ~ 15X that match or exceed that of the scanning electron microscope.
Nose or Base Strike Analysis
of Bullet Orientation in a Ricochet
Observations
on the Composition of Breech Gunshot Residue from a .22 pistol
205 KB pdf file (approx. 2 mins @ 56k)
People v. Aceves:
A Case of 22 Caliber Gun Shot Residue Matching
1,990 KB pdf file (approx 10-12 mins @
56k)
This is the analysis of a shooting where the assailant shot
the victim twice with a .22 revolver. The ammunition was Remington with a single metal primer. The weapon attributed
to the shooting is shown to have likely last fired Federal three-metal primered ammunition and thus could not have
been the weapon used in the shooting. This paper examines the effect of previous-shot gunshot residue (GSR) contamination
as well as the GSR compositional differences in samples from the breech, target and bore. This work also shows
that the accumulation of GSR within a .22 revolver, especially from different ammunitions, makes the resultant
GSR composition from a shot unpredictable. The antimony that covers most modern .22 bullets is likely to contribute
substantial amounts of antimony to the GSR of some shots.
Failure of a
Security System Due to Motion Sensor Cover Failure
2,480 KB pdf file (approx 12-15 mins @ 56k)
Six security motion devise covers were received for analysis
following apparent failure of the security system in a tire/brake store burglary. Four of the covers of these thin
plastic sheets were from failed devices and two were controls. The control covers were from devices that operated
normally. The covers were examined by normal light, ultraviolet light transmittance and scanning electron microscopy/elemental
analysis. The submitting party suspected that some sort of material was sprayed on these covers, rendering them
inoperative. The results of these analyses indicated no evidence of human manipulation. Rather, it is apparent
that environmental factors likely caused the degradation of the plastic covers which resulted in the failure to
allow the radiation specific to the motion detector to pass through.
Skin Debris and
Gunshot Residue Samplers: I. The Particle Habitus
2,303 KB pdf file (approx 12-15 mins @ 56k)
A series of experiments were performed to determine how skin
debris (desquamated epithelial cells and skin oils) affects gunshot residue (GSR) particle detection on SEM stubs:
1) A dabbing experiment showed that GSR particles accumulate not only on the adhesive surface of the sampler, but
also on the epithelial cells. 2) A bleach solution made up of sodium and calcium hypochlorite was used to remove
skin debris from gunshot residue samplers. This bleach treatment revealed particles that were originally hidden
by skin debris. Skin debris not only accumulates GSR particles, but also obscures particles.
Skin Debris and Gunshot Residue
Samplers: II. The Issue of Acceleration Voltage
836 KB pdf file (approx 4-6 mins @ 56k)
A sampler was initially loaded with target gunshot residue
(GSR) and then was dabbed 30 times on the back of a hand. A number of high-resolution (4096 x 4096 pixel) backscatter
images were taken at 20 kV and then at 30 kV of the same areas. Following these images, the sampler was treated
to remove skin debris with a sodium/calcium hypochlorite solution and additional high-resolution images were taken
at 20 kV of the same areas. Comparison of these images shows that more GSR particles are revealed at 30 kV than
at 20 kV. The removal of skin debris evinced even more GSR particles that were not detected on the untreated samplers,
regardless of the acceleration voltage used.
Errors
in gunshot residue assessment by scanning electron microscopy/elemental analysis in criminal cases: I. Arsenic/sulfur
mistaken for lead.
276 KB pdf file (approx 2 mins @ 56k)
Automated scanning electron microscope analyses of gunshot
residue samplers are being performed by many crime laboratories all over the world. Often the criminalist-technician
operators of these instruments do not have adequate training for the interpretation of spectra generated by energy
dispersive X-ray spectroscopy. Case 1 is an example of this. Case 2 is an example of a criminalist who appeared
to have misrepresented the elemental composition of a particle in order to make it "unique" to gunshot
residue. This article is the first in a series of four articles that will focus on erroneous elemental assignments
and/or missed elements made by ill-trained criminalists. The mistaken assignments of particle spectra to "consistent,"
"highly specific" or "unique" gunshot residue will also be examined in this article series.
Errors in gunshot residue
assessment by scanning electron microscopy/elemental analysis in criminal cases: II. Missed tin (Sn) and antimony
(Sb) in an unusual, non-gunshot residue population of particles containing phosphorus (P).
677 KB pdf file (approx 4-6 mins @ 56k)
Automated scanning electron microscope analyses of gunshot
residue samplers are being performed by many crime laboratories all over the world. Often the criminalist-technician
operators of these instruments do not have adequate training for the interpretation of spectra generated by energy
dispersive X-ray spectroscopy. In this case, a number of unusual particles, most of which contain phosphorus (P)
and tin (Sn) were assigned by the criminalist as being "unique" to gunshot residue. Unfortunately, none
of the particle spectra recorded in this case can even be assigned as "consistent," much less "unique"
to gunshot residue. Errors made by this technician are 1) missed elements, tin (Sn) and antimony (Sb), and 2) including
phosphorus (P) as a gunshot residue element. The origin of these particles is unknown.
Errors in gunshot residue assessment
by scanning electron microscopy/elemental analysis in criminal cases: III. Friction-brake particles assigned as
"highly specific" gunshot residue particles.
677 KB pdf file (approx 4-6 mins @ 56k)
The previous two articles of this series (Burnett, 2005A
and 2005B) dealt with errors made by criminalist-technicians in the interpretation of element spectra. This third
article of the series will deal with the misassignment of apparent friction brake-generated particles as "highly
specific of gunshot residue" particles.
Macro imaging with digital
cameras
2.18 MG pdf file (approx 11-16 mins @
56k)
We examine six digital cameras (all manufactured by Pixera
Corp), made for scientific and industrial applications, as to their capabilities for depth of field imaging. All
the digital cameras examined in this study can acquire high depth of field images with a good macro-zoom lens such
as the Computar MLH-10. The Pixera 600CL, a high resolution peltier cooled CCD digital camera that is manufactured
for the fluorescent microscopy market, has truly exceptional capabilities.
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