The spectroscopic detection of drugs of abuse in fingerprints after development with powders and recovery with adhesive lifters

The application of powders to fingerprints has long been established as an effective and reliable method

for developing latent fingerprints. Fingerprints developed in situ at a crime scene routinely undergo lifting

with specialist tapes and are then stored in evidence bags to allow secure transit and also to preserve the

chain of evidence. In a previous study we have shown that exogenous material within a fingerprint can

be detected using Raman spectroscopy following development with powders and lifting with adhesive

tapes. Other reports have detailed the use of Raman spectroscopy to the detection of drugs of abuse

in latent fingerprints including cyanoacrylate-fumed fingerprints. This study involves the application of

Raman spectroscopy for the analysis of drugs of abuse in latent fingerprints for fingerprints that had

been treated with powders and also subsequently lifted with adhesive tapes. Samples of seized ecstasy,

cocaine, ketamine and amphetamine were supplied by East Sussex Police and by the TICTAC unit at St.

Georges Hospital Tooting. Contaminated fingerprintswere deposited on clean glass slides. The application

of aluminium or iron based powders to contaminated fingerprints did not interfere with theRamanspectra

obtained for the contaminants. Contaminated fingerprints developed with powders and then lifted with

lifting tapes were also examined. The combination of these two techniques did not interfere with the

successful analysis. The lifting processwas repeated using hinge lifters. As the hinge lifters exhibited strong

Raman bands the spectroscopic analysiswas more complex and an increase in the number of exposures to

the detector allowed for improved clarification. Spectral subtraction was performed to remove peaks due

to the hinge lifters using OMNIC software. Raman spectra of developed and lifted fingerprints recorded

through evidence bags were obtained and it was found that the detection process was not compromised.

Although the application of powders did not interfere with the detection process the time taken to locate

the contaminant was increased due to the physical presence of more material within the fingerprint.