GUNSHOT RESIDUE ANALYSIS

Gunshot residue consists of a variety of organic and inorganic substances. Therefore, either the inorganic (primarily metallic) or organic residues can be tested.

RML and others have found that the most specific, and most sensitive, method of detection is that for the metals lead, antimony, and barium. Copper may also be sought.

The two common analytical methods of detection of the three elements are atomic absorption (AA) and scanning electron microscopy with energy dispersive x-ray analysis (SEM/EDX). Of these, the more specific is SEM/EDX, but it is also the more time-consuming and expensive. Please consult with us before collecting any samples, as the sampling methods for one method often make it impossible to test by the other method.

Based upon the pattern of GSR on the target, it may be possible to determine the distance between the target and the muzzle of the weapon.  This may be of great importance in the differentiation between self defense and homicide.

A case in which we were involved was featured on the Discovery Channel (The New Detectives) during  1999. The program illustrates the need for high quality forensic analysis and close cooperation between legal counsel and forensic scientists.  It will be repeated later this year.

 

FORENSIC SEROLOGY

Forensic serology is the application of the study of blood, semen, saliva and other body fluids to legal matters. The field generally is comprised of the detection of enzymes and antigens, as in the identification of seminal stains or blood typing (ABO and secretor status) and DNA typing (by PCR or RFLP analysis).

An interesting application of combined forensic toxicology and forensic serology is the identification of mislabeled urine and blood samples based upon the correct assessment of their blood groups.

We also analyze blood stain patterns for direction, distance, velocity, and source.

As the explanations do tend to become long and involved, please call us regarding your needs in forensic serology.
 

PAINT CHIP COMPARISON

Paint from automobiles, spray apints and other sources can be compared to known samples or, in some cases, identified as to source by one or more techniques.

GC/MS (gas chromatography/mass spectrometry) of pyrolyzed samples can provide excellent analytical profiles of paint samples.  It does this by generating the mass spectra of the molecules which are produced by the paint as it decomposes.

FT/IR and FT/IR Microscopy (Fourier Transform Infrared Spectroscopy) can identify the organic (carbon based) components in the pigment or dyes in the paint.  With IR microscopy, this can be done with each individual layer.

SEM/EDX (Scanning Electron Microscopy with X-ray emission Spectroscopy) can identify the inorganic components of each of the layers of a paint sample.
 
 

OTHER FORENSIC SCIENCE

Even if we do not perform the analyses which are needed, we often can help by directing the client to another expert. This is particularly true in the areas of hairs and fibers, fire scene investigations,  and electrical malfunctions.  We also provide chemical analysis of fire debris.

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108 Coronado Ct.

Ft. Collins, CO 80525

(970)-266-8108
(303)-530-1169 (Denver-Boulder)

LAST UPDATE:  20  JANUARY 2008