Ice user who killed partner's baby son found guilty of murder

But the jury found Lindsey intended to either kill or cause really serious injury to Chayse, who suffered a severe brain injury, spinal and facial injuries, marks on his neck and bruising to his genitals on June 26, 2016.

He died two days later in hospital.

The foster mother of Chayse's mother, Michelle Dearing, said she was relieved  the trial was over.

"What I honestly think of him is that he can rot in hell," the foster mother Mariah Strahan said.

She said she hoped every day in prison was a reminder of what he had done.

"I hope the rest of his days are lived in torture, like what he did to Chayse."

Michelle Dearing, her hair pulled back, breathed heavily as the jury left the courtroom.

Ms Strahan said Chayse was a beautiful little boy.

"He was happy all the time, that was taken away from all of us," she said.

"It's not easy for (Michelle), it's not easy for anyone who loses a child."

Ms Strahan said the case had been "torture".

"It's been very hard for all of us to sit in court and listen to the injuries that Chayse had. Anything that's gone on, it hasn't been easy for any of us," she said.

"(Michelle) was devastated that she's lost Chayse and nothing is ever going to bring Chayse back. But we're relieved, too, that now the whole of Australia can know that he did murder Chayse."

"You can't explain what he did, none of us will ever know why he did it, we still will never ever know why he did it. It's just obviously the evil within him."

Chayse was a healthy and happy baby when his mother, Michelle, and two women left the infant with Lindsey in a Glenroy unit so they could go to a 24-hour Kmart.

All four adults smoked ice in the hours before the women left Chayse with Lindsey, but he admitted to police later he had been awake for days on end.
At 8.21am Lindsey phoned Ms Dearing to report Chayse wasn't breathing, and the women returned soon after to find emergency workers treating the baby, who was bluish-grey and had blood around his nose.

Lindsey and Ms Dearing had been together three months and were engaged two days before Chayse was attacked.

Lindsey told Ms Dearing and police Chayse was sleeping on his chest when he saw a spider and bolted up, causing the baby to fall and hit his head on a heater.

Defence counsel Scott Johns, SC, said the medical evidence showed the baby was shaken, and said the marks on his neck and groin could have been caused when Lindsey tried to rouse Chayse, or as they slept.

But prosecutor Nick Papas, QC, told the jury Lindsey lost control, became violent and intended to cause harm.

A neighbour told the trial he heard Lindsey call "Hey you" dozens of times about 8am, swearing, the sound of stomping and also a panicked howl.

Another witness said Lindsey admitted he had "wigged out" after being awake for days and using ice, and punched and kicked Chayse.