Thrill killers jailed for life for murder of Aaron Pajich

Two thrill killers have been jailed for life, for teaming up to kill autistic teenager, Aaron Pajich, in Perth's south.

Jemma Lilley and Trudi Lenon will spend a minimum 28 years behind bars for his murder in 2016.

The women used the 18-year-old's love of computer games to lure him to Rockingham Shopping centre, and then their Orelia home.

He wouldn't make it out alive.

Mr Pajich was garrotted and stabbed.

His body was then buried in the backyard, under a crude concrete slab.

"I hope you rot and you live to regret what you've done," stepmother Veronica Desmond said.

During sentencing, Justice Stephen Hall said Lilley and Lenon killed for their own pleasure.

"You made sure there was no chance he would escape from that house alive", he said.

The court heard the women fed each other's sick fantasy world - filled with horror movies, sexual fetishes and blood-lust.

"The loss of a child in these circumstances is every parent's worst nightmare", said Justice Stephen Hall.