Here Nejolla Korris – sometimes known as the Human Lie Detector – tells TheJournal.ie how she helps police forces sort the innocent from the guilty.

THERE IS A lie detection methodology called SCAN, which stands for Scientific Content Analysis. There are five of us in the world that are qualified to teach the methodology, and we do that with various law enforcement and military groups. It’s an interviewing tool; it’s about: how do you get information from the people you are interviewing, how do you determine whether what they’ve told you is truthful, and how do you develop a line of questioning after that to elicit the truth?

You can interview anybody. It doesn’t matter whether it’s a petty criminal, or a sophisticated fraudster. I’ve worked in civil settings where we’ve interviewed professionals about conduct allegations – so that could be anything from accountants to lawyers.

Contrary to popular belief, it’s not like reading tea leaves. There’s a specific set of markers we apply to every statement. What we look for are the consistencies in the language. So for example, one of the first things is looking at the use of the pronouns, and is that consistent. So that could be somebody saying: “I got up this morning, I took a shower and got dressed, went to the kitchen, we left for work at…” With that it is very obvious, from the shift from the ‘I’ to the ‘we’, that somebody else was in the picture at that time. So some questions might be ‘Who was there with you?’

Or there might be pronouns being used and then all of a sudden none. Missing pronouns can be an indication that the person is either distancing themselves from what they’re reporting, or it didn’t happen.

The bulk of my work is false allegations of sexual assault. Normally it’s the lawyer coming to me and saying ‘My client has been accused of sexual assault, and he or she claims vehemently they didn’t do it.’ Then I get the statement the victim has given to police. And based on that, I can tell what happened and what didn’t, and what kind of questions to ask at the trial.

A person who has lived through a traumatic event lives it again at the time they report it. A sexual assault or a rape is a very long story for the victim, it’s not wiped from the memory. So you’ll see that people will commit to an event via their language; whereas a person who is making it up won’t have the same sort of traumatic recollection of it. I’ve seen women write things like ‘I woke up the next morning and I felt like I had been raped’. Well, if you’re raped, you know it.

‘It’s our job to be very diligent’

I’m cautious. When I get a statement in front of me, I go in and put the preliminary markers in. Then I leave it for a few hours and go back. When you’re working on a sexual assault, a homicide, an arson, it’s our job to be very diligent. That just because we might see a marker or two, we don’t jump to the conclusion that all of a sudden the person’s guilty. Any statement I take, I’m going to be flushing it out for two weeks. Because if I’m using my intuition, or anything like that, then I’m doing the statement an injustice.

You can be a good liar, in terms of seeming like you’re convincing. But with this methodology, we basically say that if you’re sane, the methodology will work on you. Even the best analyst using this – if I were to sit somebody down in a room who’s used this methodology for ten years, and ask them to write a statement, they consciously could avoid using some of the typical triggers, but unless they wrote it and then had the time to edit it and flush it out, they wouldn’t be able to be perfect at it.

One success that I can talk is where a girl alleged that a man had raped her. And based on the victim statement that had been given to the police, I said it didn’t happen. This guy was a prominent member of the community. He said “At one point I think everybody thought I did it.” He didn’t. But with those kinds of allegations, people are painted for good.

There was also a case where two girls had accused a schoolteacher of sexually assaulting them. It didn’t happen, it was a completely vengeful accusation made by two girls. The mistake that the school headmaster had made was always interviewing them together. When you want to find out what happened, you need to interview them separately, because then you’ll find out whether the stories are consistent. I think sometimes people don’t want to get to the bottom of things; they’re so concerned with making assumptions that young girls wouldn’t lie about stuff like this. But young girls are really good liars, actually.

I think our society right now, we’re obsessed with this notion of lying. Everybody lies. The American Psychological Association says everybody lies 13 times a day at least. What they class as a lie is like, if I ask you ‘How you are today?’ and you say ‘Fine’, when you’re not. That’s classed as a lie. But I’m perfectly fine with people lying. We lie because we want to hide something, because we don’t want to get into the details of a story, and we also lie to preserve the peace.

As a general rule, we say you never use these techniques on your family and friends, because then you won’t have any. But if you ask my son, he’ll tell you he has never lied to me. He says “It’s just not worth it with her.”

As told to Michael Freeman. Nejolla Korris is the CEO of InterVeritas, which provides anti-corruption consulting, interviewing and interrogation training, and investigative services and statement analysis. Nejolla is an international expert in the field of Linguistic Lie Detection and has as analysed documents for fraud, international security, arson, sexual assault, homicide and missing persons’ cases; she recently assisted gardaí investigating the cold-case murder of Brian McGrath.