A Perth man accused of murdering his then-partner almost two decades ago told a friend he had burned the young mother's body in a 44-gallon drum, a jury has been told.
Chris Blennerhassett, 46, has pleaded not guilty in the Western Australia Supreme Court to killing 23-year-old Rebecca Anne Delalande in Perth's eastern suburbs in November 2001.
Her body has never been found.
Opening the trial on Monday, prosecutor Ben Stanwix said it would be alleged Ms Delalande died violently at the hands of Blennerhassett during an argument before he disposed of her body to prevent it from being discovered.
A sex worker and heroin addict who was frequently in contact with police, Ms Delalande had lived a "chaotic and itinerant" life in the years before her death and had been unable to keep her young son from a previous relationship.
Detectives only learnt she was missing in late 2017 while investigating a separate missing person case.
But any trace of Ms Delalande, including financial and medical records and interactions with police, disappeared midway through November 2001 when she was in a de facto relationship with Blennerhassett, Mr Stanwix said.
He said the jury would hear evidence from several witnesses who claimed to have seen Blennerhassett carrying Ms Delalande's limp body from his shared house in Seville Grove, east of Perth, after the pair had been in his bedroom.
Blennerhassett told one housemate he had headbutted Ms Delalande and he was taking her to hospital because she was "out cold", Mr Stanwix said.
But upon returning the next morning, Blennerhassett allegedly said Ms Delalande was dead and he had burned her body in a 44-gallon drum.
Mr Stanwix said Blennerhassett had admitted in a police interview to carrying Ms Delalande from the house but claimed it was because she was drug-affected, adding that she had been conscious when he dropped her off.
The jury would also hear evidence that Blennerhassett had been unhappy with Ms Delalande's drug use and that the accused had access to a set of industrial factory units in Bayswater owned by his father.
Blennerhassett confessed to another girlfriend that an ex-partner had "died in his arms" from a heroin overdose, Mr Stanwix said.
"She died in his arms because he struck her and killed her, angry that she had taken those drugs," he said.
The trial continues.