Forensic expert reveals the one mistake serial killers make that always gets them caught

In spite of the mass of harrowing 'true story' documentaries, chilling TV adaptations and serial killer podcasts circulating at the moment, the majority of true crime lovers will likely never be able to place themselves into the minds of some of the world's most villainous murderers.

That said, however, those responsible for solving their heinous crimes are often given an insight into the horrific motivations and stomach-churning methods.

And every so often, criminal investigators will share a haunting insight into the crimes that defined their careers.

As is the case for forensic expert Jo Millington, who spoke to LADbible Group this week about her experiences dealing with some of the most twisted murders that have plagued the UK.

Among her various expertise, Jo - who is nationally famous for her part in catching a 7/7 London bomber - has also shed light on the one vital mistake that she's observed countless murderers make.

"We've got technology up the wazoo to detect crime, to understand what people have done, to detect trace amounts of evidence," she said.

"They go to quite extreme efforts sometimes to get rid of the evidence, but in every single case - certainly in my experience - every contact leaves a trace, right?

Jo revealed one mistake that murderers commonly make. (Ashley Cooper/Getty)

"So, it's impossible, frankly, to eradicate every single jot of evidence in a crime scene. So, the mistakes that they make - apart from not really fully understanding the potential of forensic science - is they forget that they're leaving traces of themselves on every surface that they touch, on every path that they take.

"We've known about finger prints for centuries, and yet it's probably one of the main ways in which people are identified.

"So, you kind of think to yourself, 'How did you forget that you leave fingerprints?'."

Opening up on one of the most surprising mistakes she observed a killer having made, she explained: "The perpetrator had taken the blood of his victim and he'd written a horrible word on the wall and then done an exclamation point, and in that point was his fingerprint in the blood of the victim."

Jo spoke about one particularly case that left her mind blown. (LADbible TV)

Jo went on to admit: "You kind of think to yourself, 'What an idiot'. I mean seriously, did you not think that was gonna lead to your detection?"

The forensic veteran pointed out that killers can try to clean up a crime scene to their hearts content, but at the end of the day, there will always be a spot of blood left behind which will prove vital to her team.

"Between the tiles of the bathroom, there's grout that soaks up blood like a sponge."