POWDER SUSPENSIONS OPERATIONAL PERSPECTIVE SPSA FORENSIC SERVICES GLASGOW

POWDER SUSPENSIONSOPERATIONAL PERSPECTIVE

SPSA FORENSIC SERVICES GLASGOW

POWDER SUSPENSION OPERATIONAL PERSPECTIVE

Background

Academic Research - ‘New techniques’

Operational validityBetter?

• Effectiveness• Efficient• Ease of use


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


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


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


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


Murder:- footprints on bonnet


Powder and photography


After Powder Suspension


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)


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


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


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


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

Documents

POWDER SUSPENSIONS OPERATIONAL PERSPECTIVE SPSA FORENSIC SERVICES GLASGOW