More psych tests for accused triple killer

A 20-year-old Perth man charged with the murders of his mother, eight-year-old brother and 15-year-old sister may face a Supreme Court hearing to determine if he is mentally fit to plead.

Teancum Vernon Petersen-Crofts was charged with three counts of murder the day after his mother Michelle, 48, and little brother Rua were found dead inside their Ellenbrook home in July last year.

His sister Bella was found critically injured in the backyard and died on the way to hospital.

At his first court appearance, Petersen-Crofts rambled to the magistrate about his "mamma" and "painting a picture of Jesus". He also told a security guard standing by his side that he looked "like a serial killer".

He was immediately sent to a psychiatric facility for assessment and remains there.

Petersen-Crofts appeared via videolink in Stirling Gardens Magistrates Court on Wednesday, when prosecutor James Mactaggart said that if a pending fitness to plea report made the same recommendation as a previous one, the state would ask a Supreme Court judge to determine his mental state.

The matter was adjourned until November 27.

Just after the murders, an investigating senior homicide squad officer said it was "potentially the most horrific crime scene" he had been sent to.