Luke Hanif Sekkouah pleaded guilty in the WA Supreme Court to Erica Hay's murder in Perth's southern suburbs in April 2024.
The 37-year-old was sentenced on Friday to life imprisonment, with a non-parole period of 24 years.Â
Sekkouah stabbed Ms Hay in the head, neck and body, piercing her heart, liver and lungs, in a "sustained, relentless and brutal" attack, Justice Natalie Whitby said.
"She could not defend herself against your rage and you were armed with a deadly weapon," she said.
One of Ms Hay's daughters was in the home during the attack and might have seen her dead mother lying on the floor, the court was told.
"After you repeatedly stabbed her and she had fallen and hit her head, you continued to stab her," Justice Whitby said.
"Erica was defenceless against your violence.
"Erica's injuries were horrific."
Sekkouah, a methylamphetamine user, left the house and bought a six-pack of beer from a nearby liquor store.
He then stole a bottle of turpentine from an IGA supermarket and returned to the home.
In the early hours of the next morning, he poured it on Ms Hay and some furniture and ignited it.
"Your intention to incinerate Erica's body after you had killed her was a vile and degrading act," Justice Whitby said.
"This attempt to cover up was deliberate and planned.
"Your offending is the most extreme form of domestic violence."
Sekkouah, who was covered in tattoos and sat motionless in court, then scooped up Ms Hay's daughter and ran from the house to a neighbour's home and asked them to call emergency services.
Firefighters found Ms Hay's partially burned body lying in a hallway.
Sekkouah, a mechanical fitter, told police he was sleeping in the house when it filled with smoke and he ran out after grabbing Ms Hay's daughter.
Detectives became suspicious when they learned Sekkouah had not suffered from smoke inhalation and saw Ms Hay's 23 injuries.
Ms Hay was a mother, daughter, sister and a friend, Justice Whitby said.
"No term of imprisonment can measure the value of her life," she said.
"She had so much life ahead of her."
Sekkouah initially fought the murder charge, pleading guilty on the first day of a trial.
He then disputed the facts, triggering a multi-day hearing to resolve the issues.
Justice Whitby was scathing of Sekkouah's apology letter, saying his "sustained and deceptive conduct demonstrated a lack of remorse".
The court heard Sekkouah suffered Post Traumatic Stress Disorder and lacked the skills to manage relationships. He drank alcohol and used cannabis daily.
Outside of court, Ms Hay's childhood friend, Amanda Broad, said she hoped Sekkouah "rots in hell" and he should not have been given a non-parole period.
"I just want my friend back and I'm never going to get her back," she said, crying.
"He gets to sit pretty in prison ... my friend doesn't, my friend is gone."
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