To the casual observer, Jemma Lilley and Trudi Lenon lived banal lives in Western Australia. The pair shared a three-bedroom home in a Perth suburb, where Lilley worked as a night manager at a supermarket; Lenon was raising two young sons from a previous marriage. Neither of the women had a criminal record.

But beneath the surface, disturbing thoughts of death and violence occupied their minds, a judge said this week. Lilley, now 26, had written and self-published a book about a serial killer named “SOS” — a nickname she would later adopt to describe herself, court documents said. She also reportedly told a friend that she wanted to kill someone before she turned 25, leading her to be dubbed the “bucket list” killer by some news outlets.

Lenon, too, had developed an alternate persona she called “Corvina,” who represented the 44-year-old's submissive fantasies and her desire to derive pleasure from pain, according to court documents.

In May 2016, shortly after the women moved in together, Lilley and Lenon began hatching a plan to lure someone to their home and kill him. They settled on an 18-year-old man with autism named Aaron Pajich, who was also a friend of Lenon's teenage son — and so probably more trusting and vulnerable, Judge Stephen Hall said.

In the weeks to follow, the women bought a large drop sheet and significant quantities of hydrochloric acid. On June 13, 2016, the women met Pajich in the parking lot of a nearby shopping center and drove him to their home.

Though the women would later dispute their exact involvement, it was irrefutable that a brutal murder — involving a knife and a wire garrote — took place next. Pajich was strangled with the garrote with such a ferocity that the wire probably broke during the attack, Hall wrote. Pajich was also stabbed three times, and at least two of those stabs — one to the neck and one to the chest — were fatal.

“The garrote caused fine abraded bruising to his neck,” Hall wrote. “There were also defensive wounds to his hands, showing that he made some desperate and futile attempts to resist the attack upon him.”

A jury convicted Lilley and Lenon of murder in November. On Wednesday, they were sentenced to life in prison, to serve no fewer than 28 years each. In his sentencing statement, Hall excoriated the women for their lack of remorse and said they had been driven to kill “not ... by hatred, a desire for revenge or the hope of personal gain,” but simply for the thrill of it.

“The idea of killing another person was something that excited both of you,” Hall wrote. “You saw it as a fulfillment of your shared fantasies. You hoped and expected to derive pleasure from the [violence] of taking a life.”

There was also nothing that indicated they regretted what they had done in the days after the murder, he added. Together, the women bought tiles and cement and buried Pajich's body in their back yard; the day after the killing, Lilley texted Lenon to thank her and said the killing had been “incredibly empowering,” court documents showed.

“You are welcome SOS,” Lenon responded, according to court documents.

Lilley also reportedly could not help but boast of the killing at work a few days after it happened, describing “in graphic detail” how she had stabbed the victim and how much blood there had been, court records said.

“You said it had not gone to plan because the wire garrote had broken and you had to get Trudi Lenon to hold the person down,” Hall wrote. “You joked that the police were dumb and would never catch you. ... Having fantasized about it for so long you could not contain yourself, and your bragging about it was consistent with strong sadistic tendencies.”

Lilley later backtracked and told her “distressed and concerned” co-worker that she had fabricated the story, court documents said.

Lilley and Lenon also planned to get tattoos — a jester with a knife in hand for Lilley and a symbol with the letters “SOS” and “C” (for Corvina) for Lenon — to commemorate the murder, Hall wrote.

Contrary to Lilley's boasts to her co-worker, the police investigation was “remarkably fast and thorough,” Hall wrote. Authorities quickly determined through phone records that Lenon had been the last person to call Pajich, court records stated. In addition, both women were captured on security cameras buying hydrochloric acid and meeting Pajich in the shopping center parking lot on the morning of his death.

Police interviewed both women at their home about a week after Pajich's murder and discovered the newly tiled section of the back yard. During the trial, Lenon said that she thought they were engaged only in role play and blamed Lilley for the murder. She also provided references that stated she was a good mother.

Hall dismissed those arguments, saying that the murder was the result of a joint plan and that both had lied to the police to try to cover up what had happened afterward. Moreover, Lenon did not object when Lilley asked one of her children to help them tile over the portion of the back yard where the body was buried, Hall said.

“Of course the child had no knowledge of the significance of what he was being asked to do — but you both did,” Hall wrote. “This was a murder that you planned and executed together. .... It would be artificial and inappropriate to conclude anything other than that you are jointly and equally responsible for what occurred.”

Speaking to reporters outside the courthouse after the sentencing, the victim's mother, Sharon Pajich, called Lilley and Lenon “disgusting animals,” the Guardian reported.

“He was my precious little boy. He was my firstborn,” Pajich said, according to the newspaper. “He was full of life. They deserve everything they get for what they’ve done. They’ve taken an innocent boy from his loved ones.”

The pair will get credit for time served since being arrested in June 2016, the judge said. Both women have had a rough time adjusting to life in prison, according to the Sydney Morning Herald. Lenon had to be moved to a protected unit after another inmate poured boiling water on her, while Lilley has been periodically isolated “due to concerns for her safety,” the newspaper reported.

Read more: