Jemma Lilley murdered Aaron Pajich. (Facebook/ WA Police)

A British woman has been convicted of garrotting, stabbing and burying the body of an autistic teenager in Western Australia.

Jemma Lilley, of Stamford, Lincolnshire, murdered 18-year-old Aaron Pajich at her home in Perth, burying him in a shallow grave and covering it with concrete and tiles.

Lilley said murder was on her ‘bucket list’ as something to complete before she turned 25.

Once she’d completed the gruesome task, Lilley claimed she was ‘so full of herself and euphoric’ that she couldn’t help but boast to a work colleague, prosecutor James McTaggart told the court.

Veronica Desmond, the stepmother of Aaron, simply said ‘We love you Aaron’. (PA)

The 26-year-old, who was convicted alongside 43-year-old housemate Trudi Lenon, had previously written a book about a serial killer called ‘SOS’ and went on to assume the identity of the character, the Supreme Court of Western Australia was told, during the four-week trial.

Speaking to The Times after the conviction, Lilley’s stepmother, Nina Lilley, 48, said: ‘The book was a big problem with me. At the beginning I was, ‘Fair enough you want to write a horror story’, but I didn’t like the contents of it.

‘She had always had an obsession with serial killers but she said it was a way of venting her frustration of what happened when she was a child.’

The mother of Aaron Pajich, Sharon Pajich, said she was ‘heartbroken’. (PA)

The victim – described by his mother as a ‘precious little boy’ – was lured to his death on June 13 last year, with both defendants blaming each other for the killing.

Lenon told the court Lilley approached the teenager from behind as he installed games on her computer, garrotted him until the wire broke then stabbed him three times.

The prosecution said Lilley left incriminating messages to her ‘obsequious and sycophantic’ follower Lenon hours after the killing, saying she was feeling things she had ‘not felt before”.

The trial, at the Supreme Court of Western Australia, lasted for four weeks. (PA)

After the verdict, the victim’s emotional mother Sharon Pajich told reporters she was ‘heartbroken’ and would have to deal with what happened to her son for a lifetime.

His murderers were ‘disgusting animals’ and should never be released, she said.

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‘He was my precious little boy, he was my first-born … he was full of life.

‘They (the killers) deserve everything they get for what they’ve done, they’ve taken an innocent boy from his loved ones.’

His father, Keith Sweetman, and stepmother, Veronica Desmond, who attended the trial every day, only said ‘We love you, Aaron’ and were happy with the verdict.

Lilley’s father Richard Lilley, who flew from England to watch his daughter being convicted, said nothing as he left the court building.

A jury took less than three hours to find them both guilty and they will face a sentencing hearing on February 23.

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