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

Abstract

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 fingerprints were deposited on clean glass slides. The application of aluminium or iron based powders to contaminated fingerprints did not interfere with the Raman spectra obtained for the contaminants. Contaminated fingerprints developed with powders and then lifted with 2 lifting tapes were also examined. The combination of these two techniques did not interfere with the successful analysis. The lifting process was repeated using hinge lifters. As the hinge lifters exhibited strong Raman bands the spectroscopic analysis was 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.

A competitive enzyme immunoassay for the quantitative detection of cocaine from banknotes and latent fingermarks

“…Additional information in a forensic context, such as the use by or recent exposure of an individual to illicit drugs, could provide enhanced evidence between a fingermark and a suspect. The successful detection of cocaine and other drug compounds in latent fingermarks is known using a number of different analytical approaches, and is particularly well-described for prints artificially doped with the compound of interest [14][15][16][17].…”

“…The immunodetection of cocaine on banknotes is limited to the application of strip-based immunoassays originally developed for qualitative detection of the drug in urine [24,25]. The detection of cocaine extracted from doped fingerprints is similarly focused on MS-based approaches, such as desorption electrospray ionization (DESI)-MS [15] and SALDI-TOF-MS [16] or Raman spectroscopy [14,17].…”

The spectroscopic detection of drugs of abuse on textile fibres after recovery with adhesive lifters

“…In our previous work we had already obtained reference spectra from all the seized samples [1,2]. This also enabled us to remove from the study any samples with fluorescence problems that could not be diminished by photobleaching.…”

“…In previous studies we have demonstrated the ability to use Raman spectroscopy to characterise drugs of abuse present in latent fingerprints following development with powders and recovery with adhesive lifters [1,2]. Other work has shown that samples of pure drugs can be detected on clothing using Raman spectroscopy [3].…”

“…Our previous studies have shown that it is possible to detect drugs of abuse through adhesive lifters and also through evidence bags [1,2]. The detection through evidence bags is of importance as this would allow evidence to be examined without removal thus reducing the possibility of contamination and also preserving the chain of evidence.…”