Murderers, fraudsters and paedophiles are being brought to justice with the help of digital forensic evidence. Andrew Mernin meets a man who has brought CSI into the 21st Century to find out more.

He believes the digital data revolution will see electronic devices and the internet play as much a part of investigations in the future as DNA.

“Tracking mobile phone movements and activity, recovering deleted data from PCs, tracing email and websites, linking photographs with cameras and software and proving or disproving an alibi can all involve an in-depth analysis of digital data.”

“Digital data can leave as much of a trail as fingerprints and DNA. Recovering, analysing and interpreting the data requires a great deal of skill and knowledge.”

In the case of Jane Longhurst, Marshall helped investigators establish evidence to prove the last time she was alive.

“Jane had been doing some work on her PC when she disappeared and the question was asked what was the last time she was alive so we looked at what was done on that machine, which meant she was alive at that time.

“We also looked at the murderer’s computer. We discovered he had interests in violent pornography which was leaning towards necrophilia.

“We could see there were times of the day when he was active on his computer but in the day that Jane disappeared, his normal computer activity changed. I also helped with the recovery of some CCTV footage.”

According to Marshall, one of the biggest challenges for N-Gate – which he runs with his wife, who works on the biological side of forensics – is battling the technology empires of Jobs and Gates.

“The huge problem with digital forensics is that we are up against the ingenuity of Microsoft and Apple – it’s a battle between the forensics and the software retailers. We spend a huge amount of time [overcoming] that.”

Alongside murder and missing persons cases, Marshall has played his part in investigating child abuse and paedophilia.

Meanwhile N-Gate also tracks the digital trail left by fraudsters, including pirates and corrupt directors.