Inside the mind of Harpenden’s serial killer

Joanna Dennehy (Image: Archant)

A Channel 5 series investigating the lives of psychopaths delved into the life of Harpenden serial killer Joanna Dennehy, who was convicted of killing three men in 2013.

The documentary featured interviews with those close to the case, including Joanna’s ex-boyfriend and father of her two children, John Treanor.

Despite a six year age gap, the couple fell in love when Joanna was just 15 and a pupil at Roundwood Secondary school.

John claimed that outwardly she seemed like a happy teenager but she had been self-harming for years.

He said: “She hated her mum with a passion, I mean massively hated her mum and that was definite from the get go.

“Me from the outside looking in, she didn’t have much of a life. She would go to school, come home and was never allowed out.”

She left her Harpenden home to live with John, and fell pregnant at 17 with their first daughter.

But after the birth Joanna went downhill, and she couldn’t prioritise her baby’s needs above her own.

John added: “…she was doing jack s*** in all honestly. She didn’t have that need to bond with her kid.”

After a turbulent couple of years, and a stint in prison, Joanna seemed to get better before falling pregnant for a second time.

After the birth, she took up her drinking and drug use again, until one night when she finally sent John and her two children packing.

John said: “She had a knife in there [her boots], pulls it out and stabs it into the floor and says I could kill someone.”

Joanna never saw John or her children again and was homeless before settling in Peterborough.

It was there, in 2012, that she was convicted of theft, then diagnosed with an anti-social personality disorder and given medication to control the signs of psychopathy.

She ended up renting a room from a future boyfriend and victim, Kevin Lee, where she began to feel better and stopped taking her medication.

That fateful decision meant that she once again became psychopathic and violent, and she went on to murder her first victim, Lukasz Slaboszewski, after luring him to her room on the pretence of a relationship.

She blindfolded him, leading him to believe he was playing a sexual game, before stabbing him in the heart.

Developing a taste for blood, she went on to murder her next two victims in the next 10 days, a neighbour and Falklands veteran John Chapman, and her partner and married landlord Kevin Lee.

After fleeing the area she went on a rampage with accomplice Gary Stretch, picking at random two victims whom she brutally stabbed- but who survived to identify her.

Described as giving ‘no dignity to the deceased’, having a ‘lust for blood’ and no remorse for her actions, Joanna is currently serving a life sentence in prison.

She is one of only three British female murderers who will die in jail.