Serial killer Joanna Dennehy's relationship with her partner John Treanor may have triggered her 'murderous' personality change

Her sister Maria doesn't actually blame John for what happened to Joanna but she does believe that it was their relationship that triggered the darkness in her sibling

                            Serial killer Joanna Dennehy's relationship with her partner John Treanor may have triggered her 'murderous' personality change
(Source : Getty Images)

Infamous British serial killer Joanna Dennehy, who is only one of three women in the country to gain such notoriety, had a regular childhood. Her 56-year-old father Kevin worked in private security and her 51-year-old mother Kathleen was a shop manager. Both parents worked very hard to provide for their two daughters, Joanna and her younger sister Maria, with the best life they could get. Everything was going perfectly until Joanna turned 14 and met John Treanor.

Maria said in an interview that took place in 2014: "Everyone is speculating about why she turned out the way she did. I think the people, the drugs and the environment she went into triggered something dark inside her." It has since been speculated that none of the rage and darkness would have ever surfaced if she hadn't met John.

Ever since Joanna was put in jail for murdering three men and attempting to murder two more, John has been telling news outlets that she was troubled and that he was a victim of all her excesses. Maria does not believe any of his words, however. She said: "He spent nearly 14 years with her and had two children. That’s a long time to  be with someone who you thought was troubled."

 Maria does not blame John directly for her sister's slow descent into madness but she does believe that it was the beginning of their relationship that acted as the trigger for Joanna's ultimate downfall. She said: "She started to skip school and openly defied mum and dad when they banned her from seeing John. Joanna used to sneak him into the house and she wrote about him in her diary. I showed it to them. I wasn’t being mean. I just wanted my sister back."

Kevin did what any father would have done at this point and told John that his daughter was underage. That's when the couple decided to run away together and were later found living in a tent in the scrubland behind the family's garden. When her parents finally threatened to move from the area, Joanna told them that she would only leave if John could live with them. Maria said: "Mum and dad were beside themselves. They started to chaperone her everywhere and grounded her, but John would wait outside the house or near her school."

Joanna also ran away from home very frequently until, finally, even authorities became tired of looking for her and taking her back home. Just before Joanna turned 16, the police refused to intervene and she never returned to her parents' home again. Maria recalled: "Mum and dad were devastated. Occasionally she would get in touch with them, but only for money."

When Joanna got pregnant with her first child when she was just 16, she called her parents and said that she wanted to go back home. Kevin and Kathleen went to Milton Keynes to meet her and they were shocked by her state. Her head was reportedly shaven and she looked drugged.

The desperate parents tried to take her back home but it ended being just another ruse by Joanna to get money from them. She told them that they would only be able to see her baby if they paid her and they refused to do so. John and Joanna had both of their daughters in quick succession and no one, not even her parents or sister, knew where they were living.

Neither Maria, who has a daughter of her own, nor her parents have been to see Joanna since her arrest. When the younger sibling was asked in her interview why, she replied: "Why would we? She washed her hands of us a long time ago. We don’t talk about her, except on her birthday or when my mother recalls something nice about her from our childhood."

John is now married and currently lives with his wife and children in Manchester. He refused a long time ago to get pulled into a "slanging match" with Joanna's furious family but said: "You can write what you want about me. All I care about is that my children are safe."

MEA WorldWide (MEAWW) previously reported that in March 2013, Cambridgeshire found itself in the limelight after a series of murders rocked the United Kingdom. The crimes were referred to as the "Peterborough ditch murders" as the three victims of the horrific crimes — all males who died of stab wounds — were found dumped unceremoniously in ditches outside Peterborough. The murderer was later discovered to be Joanna, who has come to be known as "the most dangerous woman in the prison system".

Joanna had reportedly hunted and stabbed the men for the sake of entertainment. She told Gary Stretch, who was formerly known as Gary Richards and was her alleged accomplice: "I want my fun. I need you to get my fun."  She told a psychiatrist at a later date that she found the act of murder to be "moreish" and that, after she killed for the first time, she "got a taste for it".