Fingerprint and FootwearForensics Newsletter

April 2007 Publication No. 17/07

IN THIS ISSUE

Programme Update

- Final IRIS Build at HOSDB - Footwear R&D Group- Scene Clean-up Workshop

Summary Reports of Recent Studies- Use of Gelatine Lifts for the Recovery of

Fingerprints - Use of White Powder Suspensions for Cowlings- Ninhydrin Marks on Thermal Receipts

Equipment Update- Schott Glass Filter Upgrades- IRIS update- Evaluation of GLScan

Recent Publications- Powders Newsletters

PROGRAMME UPDATE

Final IRIS Build at HOSDB

Following a decision to cease manufacture ofHOSDB s Integrated Rapid Imaging System (IRIS)in our workshops, the final system was delivered inMarch 2007. The Fingerprint and FootwearForensics Group would like to pay tribute to theefforts of all the staff in the workshops who havecontributed to the manufacture and delivery oftwenty-five IRIS systems since 2001.

Ian Castle and Freddie Lubin putting the finishingtouches to IRIS 025.

A full update on the current position regarding IRISsupply and support can be found later in thisnewsletter.

Footwear R&D Group

Dick Johnson, SSM of Bedfordshire Police has beenappointed Chair of the National Footwear BoardResearch and Development Group. The firstmeeting of the Group was held at HOSDB on 22February 2007.Following a review by a number of forces, the groupwas able to give direction to a variety of projectswhich will be managed by Helen Bandey.

ContactsValerie Bowman 01727 816209Vaughn Sears 816216Helen Bandey 816385Alex Hart 816304Stephen Bleay 816252Andrew Gibson 816272Lesley Fitzgerald 816433Melissa Black 816295Katherine Lawrie 816295Tomasz Ciuksza 815478

Sales of Fingerprint PublicationsTamara Lloyd 01727 816454Fax 816253

AddressHOSDB,Sandridge,St Albans,Hertfordshire, AL4 9HQ, UK

Newsletter publications can be downloaded from:http://scienceandresearch.homeoffice.gov.uk/hosdb/publications/fingerprint-publications/

For further information contact: hosdb@homeoffice.gsi.gov.ukISBN 978-1-84726-298-1

Powder Suspensions

� Work on a small area at a time.

� Wash area with soapy water.

� (N.B. Can stain uPVC and porous or semi-porous surfaces permanently.)

Protein Stains

� May be possible to use soaked cloths forapplication.

� Dyes stain very effectively and perception ofclean may be difficult to achieve.

Iodine

� Alternative methods should be used for safetyand greater effectiveness

N.B. HOSDB does not recommend the use ofIodine at scenes. It is toxic, toxic for theenvironment, suspected to be toxic forreproduction and corrosive. Dichloromethane iscarcinogenic. The process requires carefulapplication for maximum effectiveness, full PPEand the solution must not be sprayed.

During the workshop, the FFF group was asked todo further work to evaluate the migration ofchemicals into typical scene surfaces. This work hasnot been sanctioned by the FFF User Group, butRentokil R&D department have offered to undertakea small study to establish whether they can identifya suitable treatment for Ninhydrin clean-up.

Whether HOSDB-recommended or alternativetechniques are used at scenes, the Chemical Agentsat Work Directive (CAD - 1998) imposes minimumrequirements on the employer, workers andsuppliers to ensure adequate health and safetyprotection in the workplace. Concerns were raisedduring the workshop about the suitability androbustness of scene risk analyses, roles andresponsibilities at the scene and measures to betaken in the event of the application of non-HOSDBmethods. These concerns have already beendiscussed at the National Scientific SupportLaboratories Conference, will be raised at the nextmeeting of the Crime Scene Investigation Board andif necessary escalated to the Forensic ScienceCommittee.

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SUMMARY REPORTS OF RECENT STUDIES

Use of Gelatine Lifts for the Recovery ofFingerprints

We have conducted a short study to determine therelative effectiveness of powders used to developlatent marks and BVDA gelatine lifts for lifting latentmarks.

A range of surfaces commonly found at scenes ofcrime were used in the study including smoothsurfaces (glass, u-PVC and painted metal) andsurfaces with varying degrees of texture (melaminekitchen worktops, laminate furniture and semi-porous painted walls). When comparing processesthat are likely to target different components of thefingerprint, it is important to use a large range ofdonors that represent a typical population. The useof only a few donors or even a standard fingerprintmay favour one process over another and so mayproduce misleading data. For this reason 70 donorswere used in this trial. Donors were asked todeposit three fingerprints only across all sixsurfaces. The fingerprints were aged for either 2days or 2 weeks. Each one was then treated withone of the following:

1. Gelatine lift of the latent mark and subsequentimaging on GLScan.

2. Fingerprint powder as recommended in thePowders Guidelines Leaflet.

3. Fingerprint powder as 2, but on the surfacepreviously covered with the gelatine lift in 1.

The graph below shows the relative effectivenessof the various recovery methods across allsurfaces.

Scene Clean-up Workshop

During the 2006 National Scientific SupportLaboratories Conference, HOSDB was asked togive clearer guidance on the cleaning up of sceneswhere chemical treatments have been used. Aworkshop was held at HOSDB in November 2006 toreview current advice and identify any major issues.Only a limited attendance could be accommodatedat the workshop: it is hoped that the following notes,extracted from the workshop output, will prove ofvalue and that the topic will be discussed further atthe 2007 conference.

A number of general issues were identified regardingthe best practice for fingerprint recovery fromscenes. Kim Warner, Greater Manchester Police,had carried out a forces survey of the use ofNinhydrin at scenes prior to the workshop. Althoughthe force experiences varied widely according to herreport, there appears to be a trend towards thefollowing principles:

1. If possible, remove articles to the laboratory,where chemical treatments can be carried outunder safe, controlled conditions for optimumresults.

2. Limit the use of chemical treatments atscenes where possible — if only small,targeted areas have been treated, they maybe most efficiently cleaned up by the staffapplying the treatment or marked up forcontractors to clean.

3. Avoid the use of inherently hazardoustreatments (eg Superglue) unless there are nosuitable alternatives.

4. Ensure that a full risk assessment is carriedout for the whole process — treatment andclean-up — and with clear responsibilitiesagreed for all concerned before any action istaken.

5. Leave a record at the scene of the exacttreatment carried out, the chemicals used andany requirements for clean-up.

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HOSDB has a responsibility to only recommendtreatments for fingerprint development which areboth safe and effective. It was agreed at theworkshop that there may be occasions, such asthe development of fingerprints with Ninhydrin,where the results may be unsightly but notunsafe. In this case sealing the treated surfacebefore redecoration should be adequate. Thisand other recommendations were recorded duringthe workshop and are shown below. Pleasecontact Val Bowman if you wish to have a copy ofthe complete workshop output.

Ninhydrin

� Ensure good ventilation post-applicationand during clean-up (the solvent usedduring application will displace air).

� Remove and destroy treated areas wherepossible, eg wallpaper and floor coverings.

� Seal the area post clean-up, eg with primer,lining paper, application of diluted PVA,prior to redecoration.

Superglue

(Refer to HOSDB Publication 30/03)

� Use only as a last resort — or use wheredeemed necessary.

� Consider whether other processes, egpowders or powder suspensions may besuitable.

� At the scene — reduce risk by securing thescene, ventilating, steam cleaning, leavingunoccupied for a time, exposure monitoring.

� If used on vehicles, we advise that theyshould be crushed — safety cannot beguaranteed for subsequent use.

Solvent Black 3

� Only use for small areas.

� Consider cleaning up immediately aftertreatment.

� Remove and legally dispose of all fixturesand fittings.

� Seal with appropriate primer beforeredecorating.

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Use of White Powder Suspensions for Cowlings

It has been reported to us that a police force hashad a threefold increase in the number offingerprints developed since changing from usingsuperglue/BY40 to white powder suspension on carcowlings. We have not conducted any work atHOSDB to confirm this, but pass this news on forinformation.

EQUIPMENT UPDATE

Schott Glass Filter Upgrades

It has been noticed that recent batches of Schottglass fluoresce. It is understood that this is becausethe Schott glass is now made in a different way. Thishas a detrimental effect on the numbers, quality andcontrast of the fingerprints visualized byfluorescence.

DFO fingerprint photographed using the fluorescingfilter.

DFO fingerprint photographed using the upgraded filter.

If you notice that your Schott glass filters fluorescethey can be upgraded by the addition of a secondfilter.

An example of fluorescing Schott glass on the leftand the new upgraded filter on the right.

Foster & Freeman will, at a cost, be able to upgradeyour filters to correct the problem. Please contactFoster & Freeman for more information.

Foster & Freeman Ltd25 Swan LaneEveshamWorcestershireWR11 4PEUK Tel: +44 (0) 1386 41061Fax: +44 (0) 1386 765351Email: sales@fosterfreeman.com

IRIS Update

As indicated in the May 2006 Newsletter, HOSDBhas now put in place a framework agreement withPerceptive Solutions for the ongoing support of IRISworkstations currently in service. PerceptiveSolutions are experienced in the support of machinevision systems based on the scientific gradecameras used for IRIS. They will also call on theexpertise of the developer of the IRIS Imagersoftware. Support of the twenty-three systems

In summary, the following information can be drawnfrom the results:

� For both gelatine lifting and powdering usedalone there is a large drop in the average gradeof the marks developed from 2 days to 2 weeks.This is consistent with previous results from thepowders project.

� For both ages of fingerprints, the average gradefor powdered marks is higher than that forgelatine lifted marks.

� For 2 day old marks, the average grade ofpowdered marks is reduced by 20% if thegelatine lift is applied prior to powdering.Gelatine lifting will transfer some of the mark tothe lift hence reducing the amount of materialavailable for powders to adhere to.

� For 2 week old marks, there is little difference inthe average grade given for powdered markswhether the gel lift has been applied previouslyor not. As marks age they harden, resulting inlittle material being transferred to the gelatinelift. Marks on the gelatine lift may be caused byan impression of the mark or material transfer.

From this we are able to conclude the following:

� Fingerprint powders should continue to be usedon non-porous surfaces as described in theManual of Fingerprint Development Techniques(MoFDT) and Powders Guidelines Leaflet.

� Gelatine lifts should not be used prior topowders as this may reduce the quality andquantity of marks found with powders alone.

� Gelatine lifts may offer an alternative solution forsurfaces that can not be treated with powders(e.g. contaminated surfaces or items that mustnot be damaged or destroyed, such as someelectrical items), although the MoFDT shouldalso be consulted for alternative processes.

Ninhydrin Marks on Thermal Receipts

Following the article on treatments for thermal paperpublished in the October 2006 Newsletter, HOSDBis aware that some forces have started to use theethanol pre-dip to prevent darkening of thermalreceipts. West Mercia Constabulary has drawn ourattention to the fact that some faint marks developedusing ninhydrin can be significantly improved byviewing them on a light box. Whilst this may not beappropriate for ninhydrin marks on standard paperarticles, the fine fibre size in thermal papers makes it

easy to distinguish the marks in transmitted light. Anexample of marks improved in this way is shownbelow.

a)

b)

Thermal receipt after ethanol pre-dip, marksdeveloped using ninhydrin. a) mark viewed inreflected light, b) mark viewed in transmitted light onlightbox

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Although the GLScan system has been optimised forthe imaging of black gel lifts, attention is drawn tothe fact that laboratory and imaging staff should alsoconsider the use of alternative light sources forexamination of gel lifts. In cases where there is morethan one type of contaminant present on the gel,different lighting conditions may reveal additionalinformation. An example is given below. Imaging of adust mark lifted from skin using the GLScan revealsskin texture (a), whilst imaging using a digital SLRcamera and low level oblique lighting (b) reveals themark in dust.

a)

b)

Footwear mark in dust deposited on skin, a) imagedusing GLScan, and b) imaged using digital SLRcamera and low angle oblique light.

The intention is to use the GLScan system atHOSDB in a range of projects, including theassessment of different types of gelatine lifter.Forces requiring more information should contactone of the Fingerprint and Footwear Forensic Groupfor further details.

RECENT PUBLICATIONS

Powders Newsletters

Following completion of the powders project byHelen Bandey, a final publication has been sent toall forces. The Fingerprint Powders Guidelines(HOSDB Publication 09/07) is primarily for theattention of Scene of Crime personnel. Thepublication contains a summary of therecommendations contained in the three specialedition newsletters (HOSDB Publications 54/04,08/06 and 67/06) about the use of powders and isintended to provide the information in an easilyaccessible way.

Image of Tom Ciuksza from the FingerprintsPowders Guidelines publication.

The information included in the publicationsrepresents contributions from a number of HOSDBand other staff, to whom we are very grateful.

delivered prior to April 2006 will be transferred fromHOSDB on 1 April 2007. Forces with IRIS havebeen informed of this change already.

Two further IRIS workstations have beenmanufactured this year. Both of these systems havenow been delivered, with the final system beingsupplied to Wiltshire Constabulary on 5 March 2007,making a total of twenty-five IRIS workstationsproduced in the HOSDB workshops.

We are now planning to identify whether there arecommercial organisations who would be interestedin taking on the manufacture of further workstations,subject to demand.

HOSDB will continue to have involvement in thedevelopment of the IRIS Imager software. It is usedin the HOSDB laboratories to run specialist camerasincluding a UV imaging facility. Revisions to thesoftware are currently underway to permit the importof a larger number of RAW file types and to allowperspective correction of fingerprint and footwearmarks not taken at perpendicular angles to the mark.

Evaluation of GLScan

HOSDB recently purchased the GLScan systemproduced by BVDA for the scanning of gelatine lifts.We have been evaluating its capabilities for theimaging of fingerprints, footwear marks and indentedwriting. The GLScan system consists of a linescancamera combined with two high intensity, high anglelight sources housed in a light- tight enclosure. Thegelatine lift to be imaged is placed on a vacuumstage and traversed beneath the linescan camera,resulting in a high resolution (>1000ppi) image.

GLScan in the HOSDB laboratory

The lighting conditions have been optimised forblack gel lifts, but lower intensity light sources arealso available for the scanning of white gels.

Tests to date have demonstrated that the system ishighly effective in the imaging of latent footwearmarks lifted using black gel lifts, with good qualityimages being obtained from marks barely visible tothe eye.

The technique has also been used to image latentfingerprints lifted from surfaces where it issuspected that contamination is present andpowdering may not be effective. Operational resultsobtained from latent marks lifted in this way resultedin the HOSDB system being loaned to Gwent Policefor operational work less than one week afterdelivery.

An assessment of the relative effectiveness ofpowdering and gel lifting of latent marks is reportedelsewhere in this Newsletter.

GLScan image of a latent footwear mark, showingfainter marks from other shoes not previously visibleto the eye.

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