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How to interrogate a serial killer

Detective interviewing a subject in a dark room

When it comes to interviewing serial killers to understand their way of thinking and solicit information from them, there’s only really one name that comes to mind: John E. Douglas.

Douglas quite literally wrote the book on the subject. In fact, he’s written several, all of which are required reading for any true crime buff. If your shelves don’t support at least one of the former FBI man’s tomes, it’s something you need to address.

When it comes to first-hand information and primary research into how psychopathic murderers think and behave, Douglas' 1995 work Mindhunter: Inside the FBI's Elite Serial Crime Unit, co-written with Mark Olshaker, is effectively The Bible.

Over the course of his highly-decorated and impressive 25-year career with the FBI’s Investigative Support Unit, Douglas established the idea of criminal profiling, interviewing hundreds of America’s most notoriously brutal killers, including Charles Manson, Robert Hansen, Ted Bundy, Edmund Kemper, The Green River Killer Gary Ridgway, 'Son of Sam' David Berkowitz, Richard Ramirez and 'The BTK Killer' Dennis Rader.

Drawing from some of the more in-depth interviews with the world’s most famous criminal profiler, we’ve painstakingly extracted all the information we need to form a picture of how interrogating serial killers should look.

Get ready to pivot or adapt

A savvy investigator will know that the killer opposite them will try to lie and obfuscate. When they get the sense that that's the case, they need to change tack a little.

'Sometimes they may try to lessen their crime or project blame - make it the victim’s fault,' says Douglas. 'But if I hear that, I just kind of laugh and joke around with them, which totally changes things. I’ve also learned to give them the sense that they’re in control or dominant over me.'

It's vital that you don't see the interview as combat or competition. Don't go in trying to win. Or at least, try to view it as a long game. Conceding ground isn’t a failure, sometimes it’s a smart way to gain progress. Let the killer think they're winning, they'll get complacent and give up information willingly.

Douglas told A&E in 2019 how he allowed Charles Manson to adopt a dominant physical position during their conversations. 'I’m 6 foot 2 inches - he’s 5 foot 2 inches,' he remembers. 'So he sat on top of a chair, on top of a credenza. I knew he would do that because he did that on the George Spahn Ranch when he had his flock of followers around him.'

This relaxed Manson; made him feel less like he was getting squeezed by a fed and more like he was back in his favoured position of dominance. In allowing this to happen, Douglas adapted to his situation quickly and cleverly.

Be mindful of your body language

We've all heard about the importance of body language when meeting new people. This is usually in the context of dating or a job interview, but it’s as true over a bottle of wine as it is across a conference desk or inside an interrogation room.

When he used to interview serial killers, John E. Douglas would always make sure he avoided sitting there with his arms crossed, looking defensive, accusatory or uncomfortable.

'Your body language should be just relaxed, not a defensive kind of posture. It should be very comfortable. Like on a date kind of thing.'

There's no good cop or bad cop

Through his years of experience, John Douglas learned the pitfalls of trying to appear to be the killer's friend. It's transparent. But act too aggressively and you'll meet resistance. Investigators need to adopt a tone midway between the two. It's friendly, it's kind, but it's not so pally it comes off as disingenuous.

Douglas said this to A&E: 'Even though I detest the crimes they committed, you wouldn’t know that by the way I interview them. When I do the interviews, I’m not shocked or horrified. You can’t do that. Some agents in my unit want to strangle the guys. Deep down, I’d like to strangle them too, but I can’t. I’m trying to get information out of them.'

One trick Douglas always used was avoiding certain harsh words. He would never say 'kill', 'murder' or 'rape' as those words sound judgemental and jarring.

'I'm trying to get him to talk so we're going to project the blame. Some killers use this projection, never accepting responsibility, not admitting that it was free will, that they had the ability to make choices and they made the wrong choices in their lives, even though they may have come from a very, very bad background.'

Approach it as a conversation, not an interrogation

No one wants to be interrogated. It's aggressive and can feel like a defeat to the offender. On the flip side, almost everyone likes a relaxed and friendly conversation with someone nice.

What Douglas always aimed to do was go into the room just looking to have a chat. 'That means if they're asking me a lot of questions about myself, about maybe my family, my job, and I'm pretty honest with them,’ he told the website Mental Floss.

'They will trust me and open up to me as long as they know that I know the case, backwards and forwards. If they start fudging on the case trying to send me down the wrong path, I will confront them, but not in a mean way. I'll laugh and say, “Look, come on. I know what you did. What are you doing here?” That’s how you gain their trust.'

Never underestimate the killer you’re interviewing

Douglas' most famous interviews occurred in the city of Vacaville, at the California Medical Facility. In that federal prison, the profiler spoke extensively with Edmund Kemper.

Douglas said this about their conversations to The Daily Mail in 2021: ‘Some killers like Kemper play up their mental instability to the courts. But he was very intelligent,' Douglas recalled of their meeting, adding that The Co-Ed Killer Kemper also 'liked to talk – he had an IQ of 145.

When trying to coax information out of a serial killer, it’s important to bear in mind that these people have spent their entire lives manipulating people and lying to them. There’s little reason to think they’ll make an exception with you. It pays to go in loaded with as much knowledge of them and their crimes as you can. Don’t assume you know it all and can outsmart them.

'If you don't look deeply into the material, you don't know who in the heck you're talking to,’ Douglas says. 'You're talking to somebody who's pulling the wool over your eyes… If an interviewer relies on self-reporting, they're going to be filled with a lot of lies coming from the person they're interviewing.’

Avoid lying

While there’s every chance that the serial killer may sit there and lie during an interview, the investigator cannot afford to. It may seem smart to blag, assume or pretend as some sort of tactic to elicit something from a serial killer, but it’s a huge risk.

If an interviewer claims to know something they don’t or have access to evidence they do not, the killer may well be able to call their bluff. Any and all trust earned up to that point is now in jeopardy.

Work out the killer's motivations

It would be unwise for anyone trying to squeeze a cunning murderer to assume that they're like all the rest. While many serial killers share similarities, each is different and unique in certain ways. The key is to work out what motivates them. They are, by their very nature, going to lack empathy to one degree or another. So, trying to make them feel sorry for their victims or the families of those victims is a long shot. Instead, try to figure out what drives them.

When authorities quiz serial killers, it's usually for one of two reasons: either to solicit a confession or to try and find out how many victims they've killed, who they are and where they are. To do this, it's vital that the interviewer establishes what makes the killer in front of them tick. Are they likely to want as minimal jail term as possible? Might they be angling for an insanity plea? Do they actually want the death sentence? Then you have to consider their level of arrogance.

Sometimes, serial killers just want to brag about what a stone-cold killer they are. That's how police got the infamous LA County 'Choke and Stroke Killer' Samuel Little to confess to his death toll of 93 victims. Once caught, he was just happy to relive his crimes. As disgusted as they were by his admissions, investigators had to calmly and methodically listen to and chart his grim revelations.