Born in August 1982 in St Albans, Hertfordshire, Joanna Dennehy is one of the only three women in English criminal history to be sentenced to life imprisonment. She shares this notoriety with Moors murderer Myra Hindley and Rosemary West, who murdered at least 10 people with her husband, Fred.

Born to Kevin, a security guard, and Kathleen, a shop manager, Joanne grew up in nearby Harpenden, with her younger sister, Maria. As a little girl she used to share a bunk bed with her younger sister Maria, who was two years her junior, and the two were so close that they invented their own secret language. Like other girls of her age Joanna was fond of her dolls and as she grew up, she became fond of makeup, doing her hair and fashionable clothes. She was a bright student, a quick learner and did well at Roundwood Park School in Harpenden. Her parents hoped she would go on to the University and becomes a lawyer and even paid for extra tuition for her. She loved outdoor games too, and played regularly for school hockey and netball teams.

Unfortunately, it started to go oddly wrong in her mid-teens, when she started skipping lessons and associated with a bunch of playful older boys. When she was about 15 she fell for John Treanor, five years her senior and ran away with him, which made her family frantic. The pair was eventually found living rough in wasteland close to the family home and made reconciliation with her parents. But the problem continued , since by that time Joanne had begun taking drugs and drinking, even turning up to school high or drunk. Ridiculously, she had two children, when she was only 16. Following the birth of her first child, she became permanently detached from her parents, as she demanded money from her parents for her permission to see their grandchild. Her relationship with Treanor also became stormy, as he discovered that Joanna was cheating on him with other men and women.

Sometimes she left home for days together or weeks on end, then return and asks for his forgiveness. In an attempt to give it a fresh start, John Treanor moved to East Anglia with his family, but her habit of drinking got worse. She worked as a labourer on farms and sometimes wished to be paid in alcohol rather than cash. Sometimes she harmed herself, cutting her arms, body and neck with razor or blades to experience unintelligible pleasure.

While Joanna was rapidly accelerating towards total destruction, her sister Maria was serving the British troops in Afghanistan. After her tour of Helmand, she traced her sister at Treanor in Cambridgeshire. But Joanne made it very much clear that she would not like Maria to interfere with her family matters. By that time Joanne became violent and her tantrums became worse. Sometimes she would kick and punch Treanor in a drunken state. During this period, Treanor discovered to his utmost terror that Joanne was sleeping with an ex-convict who introduced her to cocaine. However, Joanna did not care anything, as she began to carry a dagger in one of her boots and told friends that she often feel an intense desire to kill someone. Treanor could not take it anymore, when one day Joanne threatened him with a six-inch dagger. He took the children with him and left Joanna in 2009.

The situation gave Joanna the opportunity to become more desperate and more desolate. She drifted from address to address in East Anglia, stealing and sometimes turning to prostitution to fund her drug and drinks. She was jailed on a few occasions and also received some treatment for her mental health problems. In February 2012, she spent a few days in Peterborough City Hospital, where she was diagnosed as a patient of obsessive compulsive disorder, associated with anti-social personality disorder.

After her arrest, while she was under the custody of Bronzefield prison in Surrey, she was also examined by a consultant forensic psychiatrist, Frank Farnham. According to his opinion, Joanne had Paraphilia Sadomasochism. While Paraphilia can be termed as an unusual condition characterized by abnormal sexual desires, typically involving extreme or dangerous activities, Sadomasochists experience sexual excitement from acts involving the infliction of pain, humiliation or bondage. In other words, people associated with the said disorder, experience unusual sexual pleasure and excitement from acts involving the infliction of pain and humiliation. In fact, Joanne liked to give and receive pain.

After her release from the hospital, Joanna tuned up at ‘Quicklet’, a small letting agent in Peterborough, where she found a tiny room for accommodation. Kevin Lee, the co-owner of Quicklet, helped her to get works for doing odd jobs and helping to evict tenants, which gave her access to a number of local houses. Her first murder happened in Welland, at the north end of Peterborough, in one of those houses. In the meantime, she had met Polish warehouse worker Lukasz Slaboszewski in the town centre, and seduced him. The unsuspecting man excitedly reported his friends about his intimacy with an English girlfriend. Within a short while, on 19 March 2013, Joanna texted him to meet her urgently at the Welland address. As soon as he arrived, she stabbed him to death just inside the front door, plunging a pocket knife through his heart.

After ten days, Joanne struck again. Her boss and landlord, Kevin Lee tried to take advantage of his position and have an affair with her. Joanne allowed him to a certain extent and killed him on that fateful day, at the same house in Welland. On the same day, she committed her third murder in the shared house, where she was staying on the south side of Peterborough, an isolated area called Orton Goldhay. John Chapman, a 56 year old former navy man who was staying on the first floor of the block, was suddenly stabbed to death by Joanne. She stabbed him six times.

After committing the double murder all alone, Joanna phoned up Gary Strech Richards, whom she knew through her work for Kevin Lee. Gary Strech responded her call and immediately came to the spot along with Leslie Layton, who lived at the Orton Goldhay house with Joanna Dennehy. Ridiculously, instead of reporting the matter to the police, they helped her to dispose of the three bodies in farmland ditches and after the job was done, Joanne used the two men as her driver and went on the run. On their way, she reportedly told Gary Strech that she wanted to kill again, kill more, kill more for fun and she needs Gary to help her to get her fun. Finally, as Stretch stopped the car in Hererford, Joanne immediately jumped out and repeatedly stabbed two men at random. However, those two, Sixty-four-year-old Robin Bereza and 56-year-old John Rogers, survived her attack.

Joanna Dennehy and her accomplices were caught by police a couple of days later. In the month of February 2014, Stretch was found guilty of aiding Joanna on the two attempted murders, while Leslie Layton was found guilty of perverting the course of justice. Joanna Dennehy herself was given a whole life sentence for the triple murder and two attempted murders. She claimed that she was abused as a child, though there was no evidence to justify the claim and her family and friends insisted that she was always treated well in her early years. She confessed to a psychiatrist that she liked the idea to hunt and stab men for the purpose of entertainment and after the first killing she got a taste for it.

During sentencing, Joanna Dennehy laughed, smiled and swore as she was told that, she would die in jail.