Investigating CSI – Background material Table of Contents I ...
Investigating CSI – Background material Table of Contents I ...
Investigating CSI – Background material Table of Contents I ...
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I. OVERVIEW OF FORENSIC SCIENCE DNA EVIDENCE<br />
The work <strong>of</strong> the forensic scientist: IBMS West <strong>of</strong> Scotland Branch Meeting<br />
A well-attended IBMS West <strong>of</strong> Scotland branch meeting in early November<br />
saw Marie Campbell from Strathclyde Police forensic science department<br />
give a fascinating overview <strong>of</strong> the work <strong>of</strong> a forensic scientist.<br />
Her first point was to explain the difference between a forensic scientist and a<br />
forensic pathologist - the latter deals with autopsies while a forensic scientist<br />
deals with the scene <strong>of</strong> crime, evidence investigation and DNA testing.<br />
Forensic science divides into forensic chemistry and forensic biology. Forensic<br />
chemistry deals with drug testing, marks and unique striations on tools used in<br />
crimes such as burglary, footwear marks, fire scenes, firearms and shooting<br />
incidents, forged documents and handwriting, threatening letters or money.<br />
Drug testing is the perhaps the busiest role with thousands <strong>of</strong> cases processed<br />
every year. Fire debris is sifted through to find small pieces <strong>of</strong> evidence that<br />
would suggest a deliberate cause. The way a fire 'naturally' takes hold in a room<br />
indicates whether it was started deliberately but evidence can still be hard to find<br />
when it is covered by debris or a collapsed ceiling.<br />
Physical chemistry looks at footwear comparison and gelatine lifting <strong>of</strong>f a<br />
suspect's shoes. Footwear comparison involves the electrostatic lifting <strong>of</strong><br />
footwear if a burglar has stood, for example, on a newspaper. The footprint can't<br />
be seen but dust lifted <strong>of</strong>f the paper to see the print on foil will show the unique<br />
footwear marks that are made by an individual because <strong>of</strong> the way he or she<br />
'treads' and wears the shoes.<br />
Forensic chemistry also looks at paint comparisons - a trace <strong>of</strong> paint in a hit and<br />
run accident can link back to a vehicle. Marie illustrated the point in a local case<br />
where a kidnapper hit a tree before making his escape. Laboratory analysis <strong>of</strong><br />
the paint left on the tree was able to confirm manufacture <strong>of</strong> the car and the year<br />
it was made allowing the police to quickly identify local suspects and find the<br />
kidnapper.<br />
Chemical etching is another technique employed to uncovered erased serial<br />
marks. The plate can be dipped sulphuric acid to find out the original marks.<br />
Firearms Discharge Residue analysis is another area <strong>of</strong> investigation. Residue<br />
can be found on hands, clothing and in vehicles - part <strong>of</strong> the evidence used to<br />
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