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POWDER SUSPENSIONSOPERATIONAL PERSPECTIVE
SPSA FORENSIC SERVICES GLASGOW
POWDER SUSPENSION OPERATIONAL PERSPECTIVE
Background
Academic Research - ‘New techniques’
Operational validityBetter?
• Effectiveness• Efficient• Ease of use
POWDER SUSPENSION OPERATIONAL PERSPECTIVE
Partnership working with HOSDB and Strathclyde University
10 years MSc students for 3 months
Operational problems(Substrate/contamination/poor results/comparison)
Scoping study agreed by User group
Results must have operational impact
POWDER SUSPENSION OPERATIONAL PERSPECTIVE
History
2004 student project into recovering marks from fire damaged itemsInformation gained allowed further exploration
Short operational trials and joint researchrecovery of marks, indicated useful process for contaminated and/or wet items, fire damaged vehicles
Results indicated further uses - unknown environmental factors
POWDER SUSPENSION OPERATIONAL PERSPECTIVE
Results Significant increase on items which had been wetted (60%)
Vehicle crime - cars and cowlings > 80% on other processesquicker - 3 hours
Further recovery of marks when used as ‘last’ process on other non-porous substrates
Report results to HOSDB FFF User group
POWDER SUSPENSION OPERATIONAL PERSPECTIVE
Results
Cowlings - 100% increase in recovery 40% casework results in marks - 78% increase in identifications - 300% decrease in marks with little ridge
detail ease of photography compared to fluorescence
Resulted in HOSDB Manual of Fingerprint Development Techniques re-written.
New chapter published April 2010 and charts changed to include powder suspension
POWDER SUSPENSION OPERATIONAL PERSPECTIVE
Murder:- footprints on bonnet
POWDER SUSPENSION OPERATIONAL PERSPECTIVE
Powder and photography
POWDER SUSPENSION OPERATIONAL PERSPECTIVE
After Powder Suspension
POWDER SUSPENSION OPERATIONAL PERSPECTIVE
Drugs contamination on packaging
Poor operational recovery rates on contaminated packaging
can contamination be removed?
what is best technique for mark enhancement?
Is there a better way?
MSc project based on common packaging types and common contamination (powders/glucose solution)
POWDER SUSPENSION OPERATIONAL PERSPECTIVE
Results
Best removal technique for powdersSoft squirrel hair brush light brushing
Best enhancement technique‘Brown Taped’ packaging - VMD/Glue and dye‘Silver Taped’ packaging - Powder Suspension‘Sandwich bags’ - Superglue and powder/VMD
Best removal technique for Amphetamine PasteGentle rinse with running water
Best overall enhancement techniquePowder suspension
POWDER SUSPENSION OPERATIONAL PERSPECTIVE
Firearms
Operational poor results, 2%, compared with DNA, 10%
Is current process best?Any other factors (handling, condition)
3 strands to projectBack to basics comparison 9 techniques
Comparison of best 5 over 7200 fingerprints 4 timescales
Declared trial with Ballistics Dept
POWDER SUSPENSION OPERATIONAL PERSPECTIVE
RESULTS
SG & BY40 69% with 32% deemed identifiable
SG & White Magnetic Powder 64% with 32% identifiable
White Powder Suspension 92% with 47% identifiable
Black Powder Suspension 68% with 34% identifiable
White Powder 65% with 42% identifiable
POWDER SUSPENSION OPERATIONAL PERSPECTIVE
Declared trial
Using the same donors, prints deposited on 12 guns and packaged in poly bags as per current submissions
Both White Powder Suspension and Superglue and BY40 used
86% less prints recovered
Small numbers of repeats, further work required however results indicate significant loss.
WPS recovered more marks than SG and more detail
POWDER SUSPENSION - OPERATIONAL PERSPECTIVE
QUESTIONS??
SPSA FORENSIC SERVICES GLASGOW