Expert shares the telltale sign that someone is lying about being a murderer

Netflix's Dahmer has got a lot of people thinking about how the serial killer's crimes went undetected for well over a decade.

Now, a behavioural expert has shared the tell-tale sign you you should be looking out for if, for whatever reason, you suspect someone is a killer - or simply just lying to you.

Cliff Lansley told The Hippocratic Post you can spot a killer in a number of ways.

Alamy / World History Archive

He said: "Even the most confident, hardened killers can give themselves away with tiny signs and gestures from the face, body, and voice that suggest that they are lying.

"The key is to know what you are looking for - the reliable indicators of deception."

However, unless you're aware of what these 'tiny signs and gestures' are, they will most likely go completely over your head, which is why knowledge really is power here.

The expert also emphasised that while some signs do indicate that a person has something to hide, you have to look at the overall picture before drawing any conclusions.

"We talk about things that are safe and true, such as their family, skills, education and hopes and dreams," Lansley said. 

"During that period, we note how often [killers] blink, the normal colour of their skin, their speech rate and how they maintain eye contact. 

“Later on, when the real questioning begins, we can assess changes to these normal baseline patterns to assess discomfort, stress and lying."

Alamy / IanDagnall Computing

Lansley explained that when it comes to killers and eye contact, they will typically break it and indicate elsewhere with their body language that something is not quite right.

He said: "Breaks in eye contact indicating deception are generally accompanied by additional deceptive body behaviour."

These changes in behaviour could be a faster speech rate, or even blinking more.

That's why Lansley said that if you want to know that someone is lying, even if it's not about something as serious as murder, you should pay close attention to their 'baseline patterns' and see if there are any inconsistencies.

However, it is worth noting that you probably need to be an expert to pick this up in real time.

Investigative journalist Nancy Glass, for example, said Dahmer seemed 'completely normal' when she interviewed him, RadarOnline.com reported.

Despite this apparent appearance of normality, he went on to explain that he ate his victims because 'he wanted them to be part of him' as he was 'desperately lonely' and 'ashamed of being gay'.