Revolutionizing Fingerprint Forensics

Fingerprint analysis has long played a critical role in modern criminal investigations. Now, researchers at Loughborough University, in the UK, have developed a groundbreaking method capable of detecting drug residue from fingerprints left at crime scenes – offering new hope for previously unsolved crimes.

An Untapped Resource

Investigating barely visible or invisible fingerprints, such as those on paper or glass, can often provide crucial criminal evidence. Forensic gel-lifters, familiar to fans of dramas like CSI and used by police worldwide, are small pieces of gel used at crime scenes to recover these faint traces.

Typically used to improve image quality, gel-lifters can also collect trace materials like drug residue, explosives, and other microscopic evidence invisible to standard fingerprint visualization techniques.

Because traditional chemical analysis techniques haven’t been suitable for gel lifters, the presence of these particles has – until now - remained an almost untapped resource.

Unlocking the Potential of Gel-lifted Prints

With their revolutionary method, Loughborough University researchers Dr Jim Reynolds and Dr Ayoung Kim have demonstrated that that drug residue can be detected on gel-lifted fingerprints.

“This is the first time that analysis of gel-lifted prints for a drug substance has been accomplished.” says Dr Reynolds, a Reader in Analytical Chemistry in Loughborough’s Centre for Analytical Science.

“Since gel-lifted prints can be stored for years, the technique could be instrumental in cold cases, providing additional evidence that could either link or exonerate suspects.”

Dr Jim Reynolds and Dr Ayoung Kim focused their testing on the presence of Zolpidem – a fast-acting sleeping pill that has been linked to drug-facilitated sexual assault and drink spiking.

“Zolpidem was the focus of our research, but the method could just as easily be applied to other drug substances a person may have been handling.” explains Dr. Reynolds. “By linking chemical information to the fingerprint, we can identify the individual and connect them to the handling of an illicit substance, which may prove useful in a prosecution.

“This could be useful to identify individuals who have been spiking drinks - if the drug they’re using gets onto their fingertips, then they will leave evidence at the scene.”

How The Method Works

It has long been speculated that gel-lifted prints contain valuable chemical information and could offer more accurate drug detection.

Traditional techniques typically detect all chemicals present in a sample – including those from the gel itself – making it difficult to identify specific substances.

The method developed by Dr Reynolds and Dr Kim - called sfPESI-MS – overcomes this issue by using a rapid separation mechanism that distinguishes the drug substance from the background of the gel.

The process samples the chemicals from the gel lifters into tiny liquid droplets. The chemicals extracted into the droplets are then ionized, gaining or losing electric charge based on their properties. The drug substance chemicals are more surface active than the chemicals originating from the gel, which enables them to be separated from the mixture.

This separation method enables the direct detection of a drug substance using mass spectrometry, a technique that identifies chemicals by measuring their molecular weight.

Published in the Drug Testing and Analysis journal, Loughborough’s research team successfully tested the technique with Zolpidem-laced fingerprints lifted from glass, metal, and paper surfaces in a lab setting.

New Hope for Cold Cases

Dr Reynolds and Dr Kim now hope to work with police forces to analyze stored gel-lifted prints. They also hope to use the method to identify other substances.

“The breakthrough shows that that lifted prints and other forensic marks can be interrogated for useful information.” says Dr Reynolds. “As well as other drug substances, the method could be applied to other chemicals, such as explosives and gunshot residue.”

In the future, the technique could provide police with crucial information for cold cases, potentially leading to prosecutions or clearing individuals who were previously suspects.

"We hope to apply our method to real criminal investigation samples.” says Dr. Kim, the first author of the paper, who completed the research as part of her PhD at Loughborough. “It would be rewarding to know that my PhD research has contributed to bringing criminals to justice."

A research-intensive university, Loughborough's ambitious and entrepreneurial approach to research sets us apart from other UK universities. Over 90% of Loughborough's research was rated 'world-leading' or 'internationally excellent' in REF 2021. Our institutional strategy highlights excellence in our key strategic themes of Climate Change and Net Zero, Sports, Health and Wellbeing, and Vibrant and Inclusive Communities. Our broad course offering and campus-centred environment, as well as world-class facilities, facilitates interdisciplinarity and collaborative research spanning the arts, humanities, business, social sciences, sport, health, science, engineering and mathematics to address the most pressing challenges of our time.

Learn More

This content was paid for and created by Loughborough University. The editorial staff of The Chronicle had no role in its preparation. Find out more about paid content.