GWINNETT, Claire

JACKSON, Andrew

STORE - Staffordshire Online Repository

Easylift Three Years On: Use of this Novel Tapelifting System for Fibres Evidence Screening and Ventures into Automated Fibre Finding. Dr Claire Gwinnett, Prof Andrew Jackson, Forensic and Crime Science Department, Staffordshire University, UK Outline of Presentation   Brief overview of Easylift development and properties  Discuss the questions raised through internal/external review of Easylift  Evaluate the use of Easylift for screening for fibres from volume crime scenes  Proof of concept of a new fibre finding system     EAFS 2015 2 Current Status of Fibres Evidence in UK EAFS 2015 3 Development of Easylift  New tape system that allows analysis of fibres in situ  without need for dissection  Non-birefringent  Tape and backing does not interfere with analysis  No air bubbles  Allows analysis by;  Polarized light microscopy  Fluorescence microscopy (some wavelengths)  Raman spectroscopy  Microspectrophotometry (MSP)  EAFS 2015 4 x 400 magnification Entellan Easylift Euriscion 2013 Questions Raised from Review  Laboratory review from practitioners in the UK, the Netherlands and Canada have provided feedback . Feedback also provided through international conference workshops.  EAFS 2015 6 Can Easylift be easy dissected if required? Does the system interfere with FTIR results? Could Easylift be autoscanned to aid screening? Can the tape be made in larger pieces? Dissection of Easylift  Easier than on acetate backing  Same solvents can be used for removal of adhesive   EAFS 2015 7 Dissection of Easylift Black = Mountant, Red = Adhesive, Blue = Nylon, Yellow = Nylon in Easylift EAFS 2015 4000 3500 3000 2500 2000 1500 1000 500Wavenumber/cm-1Reflectance8 Dissection of Easylift Black = Mountant, Red = Adhesive, Blue = Nylon, Yellow = Nylon in Easylift EAFS 2015 4000 3500 3000 2500 2000 1500 1000 500Wavenumber/cm-1Reflectance9 Sizes of Easylift  EAFS 2015 10 To Screen or Not to Screen?  How do we put in place a system that does not allow the evaluative element to be damaged by the investigative process??  How do we screen appropriately? EAFS 2015 11 Cost effective, Investigative Misuse of information, ‘cognitive contamination’    Use of screening is an investigative tool NOT an evaluative role Screening for Volume Crime Scenes  3 police forces with one central scientific support unit uniquely utilising fibres in volume crime scenes  Easylift used at point of entries and car seats   Tapes screened (initially by USB microscope) now sent to Staffordshire University EAFS 2015  Initial intelligence information gathered by colour, morphology and fluorescent properties in order to potentially link scenes  Identify potentially evidential fibres for further analysis  Prolific offenders to be identified  12 Screening Procedure  Training delivered to SOCOs  Samples from   Burglary  - dwellings  Burglary – other dwellings  Samples taken from POEs and logical contact points;  Door/window frames, broken glass   Door handles, fork/spade handles  Samples sent to Staffordshire University for initial screening of colour  - no need for fibre free room  Samples analysed through bag initially – report sent   After 3 months – evidence bags opened and tapes analysed using PLM – report sent   EAFS 2015 Variety in number of tapes used 13 Documentation at Staffordshire University  Evidence Number  Socrates Reference Number  Tape Reference Number  Location – not always noted  Colour of fibres (subjective but categories used to reduce this)  Time/date EAFS 2015 14 Example of Initial Screenings  27 crime scenes analysed, 3 had inadequate packaging preventing analysis EAFS 2015 15  Idea:  To utilise a VSC 4 Plus to further discriminate between fibres held on tapes  Observe through  full wavelength range and filter options Initial Study to Identify Effectiveness of VSC in obtaining Fluorescence info EAFS 2015 16  Easy to use and view  Provided additional albeit limited additional information   Needs high magnification  Requires non-fluorescing tape and backing  Subjective  Only a preliminary stage before use of a fluorescent microscope.   Advantages and Limitations Advantages  Removes need for fibre free examination room – tapes analysed within evidence bag  Fast intelligence information in order to inform which samples to be sent to provider  Compatible with normal dissection – no interference from medium  EAFS 2015 Limitations • Full potential for PLM screening not fully realised due to current police protocols    • Care needed in how information is used • Large numbers of fibres still to be screened – automation still required • Database required to ascertain evidential value     17 Potential Strategy for Screening?  National data to identify reliable colour data  Robust inferential process to provide links between scenes and people  Re-assessment of further features to identify whether still able to discriminate  If still unable to discriminate – use for intelligence EAFS 2015 18 Fibre finder data  Images taken of 136 suspect fibres in Easylift,  one fibre per image:   Extracted and saved the RGB values of each pixel of each suspect fibre image  Took image of control fibre in DePeX:   Cropped this, thus:    EAFS 2015 19 Fibre finder data   Extracted the RGB values of each pixel of the cropped image of the control fibre, then found the frequency of each of these values in the cropped image  Counted the number of times each of the 5 most frequently occurring control RGB values appears in each of the images of the suspect  fibres.  Summed these values for each of the suspect fibres  Noted the colour of each of the suspect fibres (pink or not pink)  Ignored two outliers  Generated the kernel density plot on the next slide EAFS 2015 20 Fibre finder data EAFS 2015 21 Further Work  Easylift is currently in initial discussions regarding mass production with forensic consumables company;  Development of range of tape sizes and tackiness  Easylift project is being developed in 4 main areas:  1. Automation of tape scanning and imaging – use of 3D Histech slide scanners 2. Fibre finding through colour and optical characteristics 3. Use of Easylift as a universal tape (including retrieval of biological evidence) 4. Generation of a database of fibre populations at volume crime scenes and non-crime scenes for intelligence and prevalence information   EAFS 2015 22 Thank you for listening Thank you to: Beds, Cambs and HertsPolice, Staffordshire Police, RCMP, Netherlands Forensic Institute, Tom Schotman, Priscilla Kuijt, Joachim Gotink, Sanne Leers and Max Grundhill,  

Easylift Three Years On: Use of this Novel Tapelifting System for Fibres Evidence Screening and Ventures into Automated Fibre Finding.

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