‘She told me that she wanted to kill someone’: how an obsession with serial killers lead to a tragic murder

Jemma Lilley wasn’t like other girls her age. For as long as anyone can remember, she fantasised about torture – and murder.

From a young age, Jemma developed an unusual obsession with extreme violence. She was just 15 and living in England when she started writing a book called Playzone, about a brutal killer called S.O.S. who tortures his victims. The writing was so graphic that it horrified the teachers at her school.

Jemma’s father Richard Lilley encouraged her writing, believing she was simply being a creative young woman. “I’ve read some of it and it’s not for me. It’s not for a lot of people,” he told Sunday Night’s Steve Pennells. “It’s a little bit too graphic for me. A lot of people thought she had a mental problem.”

The character would go onto dominate her life. She had his name tattooed on her body, she signed her name S.O.S. and when she was angry she told people, “S.O.S. is coming out.”

In 2009, when Jemma was 18, she left England to begin a new life in Australia. She got a job at a supermarket in Perth. Her colleague at the time, Bobby-Leigh McGregor, recalls her initial impressions of Jemma. “I liked her. She was quick-witted and she was funny and she was very likeable.”

Soon after, Jemma shared her writing with Bobby-Leigh. “Around four or five months after we’d initially met, she told me that she was writing a book and I read it, and it was about a serial killer who had a cult following and who liked to torture their victims to death. And I just thought she was imaginative and lived in a fantasy world and had a creative imagination.”

Later, Jemma would also proudly show off her collection of butcher’s knives to Bobby-Leigh. “She showed me how sharp they were. And she had them in the black pouch, and she showed me how sharp the knife was by shaving her arm hairs with it.”

Jemma was obsessed with knives – but was also a huge fan of horror films, and with movie villains like Freddy Krueger. She became a regular customer at a video store managed by Angela McKibbin.

“She liked horror movies. And that’s the only genre she would rent,” Angela explained.

As time went on, Angela noticed Jemma’s thoughts growing darker. “She told me that she wanted to kill someone and that the feeling that she had was getting stronger and stronger,” Angela recalled. “She didn’t know if she could control it for much longer. And that she wanted to kill someone before she was 25.”

Jemma wanted a partner in her murder plan. She enlisted mother of three, Trudi Lenon. Trudi introduced her to one of her son’s friends, 18-year-old Aaron Pajich-Sweetman. Aaron lived on the same street as Trudi, and they’d known each other for eight years.

Aaron’s stepmother, Veronica Desmond, remembers Aaron as an innocent person. “He had a smile with his eyes, blue and sparkly. Even if he wasn’t smiling with his face, you could see the smile in his eyes.” However, he was different to other kids.

“His Asperger’s… He’d make friends with anyone, and didn’t see the bad in anyone.”

At school, Aaron was bullied and struggled to make friends – but he found one in his teacher, Meghan Wiasa.

“I took him under my wing,” Meghan remembered fondly. “Teachers do that in every school, every class, there is always that one wounded bird in the nest that you have to try and protect that little bit more than the others. He was my little wounded bird.”

While Aaron’s Asperger’s-like condition meant he had some learning difficulties, when it came to computers he was one of Meghan’s most gifted students. “He had some areas of intelligence that were superior,” she revealed. “Quirky computer knowledge that most people aren’t really interested in, or aren’t very good at.”

In early June 2016, Jemma and Trudi started to formulate a plan. Jemma texted Trudi: “I feel as though I cannot rest until the blood or flesh of a screaming victim is gushing out and pooling on the floor, until all the roads and streets are stained red.” Trudi replied, “It is definitely time – I am ready, you are ready.”

In preparation, the two women made several visits to a hardware store, buying supplies to dispose of a body. They even tested a small batch of hydrochloric acid, to see if it would dissolve meat. Their gruesome experiment worked, and they returned to purchase 100 litres of the acid.

The next morning, after dropping her children at school, Trudi called Aaron and invited him to her home to install some software on a computer. As he sat down to get to work, Jemma and Trudi moved in for the kill.

Trudi went outside to lock the back gate and prevent Aaron’s escape. A home security camera captures her returning. Just as she enters the house, she pulls out a large carving knife.

Either Trudi or Jemma crept up behind Aaron with a wire garrotte. Startled, he tried to bite off his attacker, before the garrotte broke.

As Aaron struggled for his life, he was overpowered by his two captors, and was stabbed three times in the chest and neck. Two of the wounds were fatal.

The plan to dissolve the body in the hydrochloric acid was abandoned. Instead, in the dark of the night, they took the body into the backyard, buried it in a shallow grave, and covered him with tiles and concrete.

With no word from him, Aaron’s parents began to worry. The police were called, and appealed for help from the public.

Jemma’s need to boast about what she’d done was so overwhelming, she bragged about it to one of her male workmates at the supermarket.

“She told him that she had finally done it,” Jemma’s colleague Bobby-Leigh explained. “He said to her, ‘What do you mean? You’ve done what?’ She said that she’d killed somebody, that she had come up from behind and put a garrotte around his throat, but their plans didn’t go the way that they’d planned it, so she had to get Trudi to hold Aaron down while she stabbed him.”

The workmate was so horrified that he called the police.

When police visited the house, Jemma taunted them by pointing out her recent handiwork – the amateurish tiling job in the backyard.

The next day, police returned to the house with a forensic team. Under the tiles, they discovered Aaron’s body.

Jemma and Trudi were charged with Aaron’s murder. While under arrest and under pressure, the two killers were about to turn on each other.

Jemma claimed she went to sleep in another room, and the last time she saw Aaron alive was with Trudi. She says when she got up, Aaron’s bag was still here, but he was missing – and so too was a piece of carpet roughly the size of a body.

In a conflicting story, Trudi told police she had nothing to do with Aaron’s murder. However, she did later admit to helping Jemma bury the body.

Jemma’s father, Richard Lilly, flew out for the trial with one question for his daughter – did she do it?

“She said, ‘No, 100% I did not.’” Richard told Sunday Night. “With the emotion in her eyes, I believe her. She swore to me that she did not play any part.”

During a five-week trial, the jury was shown a series of graphic and incriminating crime scene photos linking the murder to the women. Yet one of the most damning pieces of evidence came from the killers themselves – the chilling video caught by their own security camera taken moments before Aaron was murdered, showing Trudi entering the house with a large knife, the likely murder weapon.

The jury took less than three hours to find Jemma and Trudi guilty of murder. Judge Stephen Hall sentenced them to one of the longest jail sentences in Western Australia’s history – 28 years before being eligible for parole.

While Jemma has lodged an appeal against her murder conviction, Aaron’s stepmother Veronica has been left with many questions. “Why? Not just why Aaron, why anybody? Why would you go fetch someone that you’d known for so many years, for someone… wanting to kill, why?”

Aaron’s former teacher, Megan Wiasa, attended the memorial for her former student and friend. “There were people everywhere,” she recalls. “I remember looking around and I thought, Aaron had more friends in death than he did in life. And it shouldn’t be like that, you know? And then I thought, wherever he is, heaven or otherwise, he’d be looking down thinking, ‘Wow, look at all my friends now.’ Go and fly with all the popular kids now. Now he’s free to be as popular as he likes.”

Reporter: Steve Pennells

Producer: Margaret Parker

Our goal is to create a safe and engaging place for users to connect over interests and passions. In order to improve our community experience, we are temporarily suspending article commenting