Forensic psychologist Caoimhe McAnena spends her days working with disturbed, violent criminals. As she appears in new TV show Britain’s Forgotten Serial Killer: Trevor Hardy, which tells the story of ‘the Beast of Manchester’ murderer, Caoimhe tells us how she copes…

“Sitting in a small private room, across from an elderly gentleman talking about his life experiences, we might look like two old friends catching up. But if you look closer, you’ll notice the case files in front of me. I’m at work, as a forensic psychologist.

“Most weeks, I visit high-security prisons and meet with high-risk violent offenders – the kind that may have murdered their wives or sexually abused children. It’s my job to delve into the innermost corners of these criminals’ minds, uncovering the harrowing secrets from their past.

“Every case is different. And so is every offender. Some speak freely, others are more cautious. But as they spill the most disturbing details of their crimes, I have to mentally separate the crime from the person. By the time they meet me, most will have served their time and are up for parole. I’m there not to dwell on what they did, but to analyse why they did it – and if they are likely to do it again.

“I decide if I think they can be managed in the community or remain too dangerous to release. It can be a lot of pressure – there’s no room to make a wrong call.

“I spend around two hours talking about their childhood, criminal history and experiences that impacted on their life. Usually we’ll be alone, but prison guards are outside, and inmates are mostly polite and honest. Still, when people find out what I do – especially combined with the fact I’m a mum – they’re surprised. They usually always ask how I cope. ‘It must be a tough job,’ is a regular response.

“I suppose it does take a certain type of person, and I have to admit, it’s a far cry from what I imagined myself doing, growing up in Northern Ireland. As a little girl, I dreamt of being a ballet dancer, but when I was choosing my A levels, I came across psychology. I fell in love with the subject and during my degree at the University of Ulster, I became fascinated with clinical psychology, which deals with mental and physical health. I wanted to understand everything about people and why they did the things they did.

“After completing my doctorate in 2001, I joined the Forensic Service, working in a specialist women’s unit where I would carry out risk assessments and run therapy groups for women with mental health problems.

“It was the first specialised female-only ward in the UK and I enjoyed seeing the difference we made to these women’s lives, but when I qualified as a chartered clinical forensic psychologist in 2005, I began working with high-risk, mentally ill offenders, many with severe personality disorders. I remember the first time I went into a prison. It was HMP Brixton, an old Victorian prison, and it looked like what you see on TV. Walking across the landings, seeing the metal bars, what struck me was the cold, harsh environment, and I was surprised by the starkness of it. I felt apprehensive, but I was with a colleague, there were prison officers around, and all my training and experience meant I knew I had to treat this patient like any other.

“These days, I work across the country. One week I could be in HMP Wakefield, home to some of Britain’s most notorious criminals, such as Soham murderer Ian Huntley, and Mark Bridger, who murdered five-year-old April Jones. The next, I could be in HMP Belmarsh sitting across from a serial rapist. Before meeting an offender, I read their case files and study medical reports. The mind of a violent criminal can be a complicated place, and I can be faced with disturbing details of crimes you’d never read in any newspaper.

“And despite spending two decades delving into the most damaged minds, I’m not unshockable. In February 2016, I was asked to give my expert opinion on serial killer Levi Bellfield. He’d just revealed graphic details about how he had raped, tortured, then murdered 13-year-old Milly Dowler, after kidnapping her on the way home from school.

“I’d never looked into Bellfield’s case, so I read about him and he made my stomach turn. Bellfield made his admissions on the condition he could describe what he did to female police officers. This was him still gaining sadistic pleasure from his crimes, and trying to control women in a sexualised way. What he subjected Milly to was sickening, but serial killers like Bellfield are the rare exception. Taking a life is, for most, a very difficult thing to live with and the majority of offenders are ashamed of what they’ve done. Most want to change.

“That’s what I try to remember. When I first qualified, it took me a while to switch off all the harrowing things I’d hear. I’d find my mind drifting to cases while I was at home, or watching TV. But you can’t let work infiltrate the rest of your life. I’m not allowed to talk about cases with anyone, but having colleagues I could share the burden with helped. And now I am a married mum-of-two, I’ve made sure that as soon as I finish for the day, I switch off. And I always make sure we do something fun as a family – the things I’ve heard have proved to me how important it is to make the most of each day. Of course, I still have to process the things I’ve heard, so I do yoga to unwind and I’m a part-time lecturer at Goldsmiths, University of London.

“My job is to protect society from the dangerous and violent. And that means I see the worst it has to offer. But I also see people fight to turn their lives around. I want to help those people and, on the really tough days, that’s what I focus on.”

Caoimhe McAnena gives her expert opinion in a one-off documentary exploring the secrets of serial killer Trevor Hardy. Dr McAnena helps analyse previously unseen medical reports and documents Hardy left in his cell when he died.  

Watch Britain’s Forgotten Serial Killer: Trevor Hardy on Sunday 14 January at 10pm on Crime + Investigation, Sky Channel 553, Virgin 275, BT 328 and TalkTalk 328.