An example of the benefits of Vacuum Metal Deposition (VMD) over the traditional methods of visualisation of fingerprints with particular reference to new polymer bank notes
-Courtesy of Cumbria Constabulary, June 2017
During one evening in 2017, enquiries at an address led to the arrest of three people in relation to the illegal supply of drugs. Suspect A, B & C
The three were placed into custody.
To assist in the ability to charge suspects and potentially retain them in custody as well as complete quick turnaround times to efficiently deal with crime in Cumbria, the Fingerprint Bureau based in HQ Penrith offers the opportunity for OICs to submit urgent cases to be dealt with whilst potential offenders are sill in custody.
In this case it was decided that some of the exhibits seized at the scene (a quantity of cash from under a mattress, etc) would be urgently transported to the Chemical Laboratory for chemical treatment. The exhibits were received a few minutes prior to midday.
Three and a half hours later, the exhibits had been treated using Vacuum Metal Deposition, Ninhydrin and Superglue treatments. Gels lifts and photographs had been taken of the visualised fingerprints and two of the suspects had been identified with the OIC informed.
What makes this a case of interest?
Whilst we have always treated bank notes in the Laboratory, the introduction of new Polymer notes has meant the traditional method of treatment (Ninhydrin) is no longer suitable for £5 notes, this is due to their nature changing from a porous to non porous material. This will soon be applicable to the £10 and £20 notes.
The preferred and suggested method of treating Polymer notes is a Vacuum Metal Deposition (VMD) unit.
The addition of this VMD unit to the Laboratory has meant that we can continue to provide the same excellent level of service to our customers.
The numerous identifications we achieve is partly as a result of the treatment of bank notes and this can continue.
Fingerprints on bank notes can not only implicate suspects. They can be tied back to IPs in the case of Robberies/Burglaries, they can be used to identify previously unknown suspects and in the case of most drug cases the identification of numerous people with previous drug convictions with no ties to the case can be used to illustrate the money in question is drug money.
This case was one of the first where VMD was used and as a bonus the marks visualised were identified to the supplied suspects. In addition and hopefully to assist the enquiry, it also revealed the fingerprints of an individual picked up on a speculative search on the Ident1 fingerprint database.
Previously Ninhydrin was the chemical of choice used to treat bank notes and this was sill the case but with limited success. Local trials tended to suggest on average one in twenty bank notes will reveal a fingerprint but with regards to £5 notes, due to their size, the results are considerably poorer.
In this case VMD was used on the £5 notes and Ninhydrin was used on the £10s and £20s.
In total £1800 was submitted into the Laboratory for chemical treatment. Of the submitted cash:
x3 £10 disclosed fingerprints
x3 £20 disclosed fingerprints
x5 £5 disclosed fingerprints
£20 notes – Ninhydrin treatment
x1 of the fingerprints on the £20 notes remain unidentified
x1 of the fingerprints on the £20 notes was identified to Suspect B
x1 of the fingerprints on the £20 notes was identified to Suspect C
£10 notes – Ninhydrin treatment
x2 of the fingerprints on the £10 notes remain unidentified
x1 of the fingerprints on the £10 notes was ident to Suspect B
£5 notes – Vacuum Metal Deposition
x1 of the fingerprints on the £5 notes was identified to Suspect B
x3 of the fingerprints on the £5 notes was identified to Suspect C
x1 of the fingerprints on the £5 notes was identified to another person (shown below)
In total 132 £10 and £20 notes were submitted for Ninhydrin treatment. Six fingerprints were recovered.
132/6 = one note in every twenty two retained a visualised mark.
This is a 4.5% success rate. (This is in the ball park of the usual average)
In total 13 £5 notes were submitted for VMD treatment. Five fingerprints were recovered.
13/5 = one note in every 2.6 retained a visualised mark.
This is a 38% success rate. (This far exceeds previous results)
More fingerprints were visualised with the VMD than any other type of bank note.
Proportionately more marks were visualised on far fewer £5 notes.
All marks visualised on the £5 notes were identified.
Confirmation of identifications were with the OIC within 3.5 hours of receipt of the exhibits into the lab.
This is the result of one singular case study and results may vary after more notes have been treated