Triple murder accused had troubled history

A Perth teenager accused of killing his mother and two siblings has a history of mental health problems, his Cairns-based father says.

Teancum Vernon Petersen-Crofts, 19, has been charged with the murders of Michelle Peterson, 48, her eight-year-old son Rua and 15-year-old daughter Bella.

"From what I've heard from other family members, he was rejected for whatever reasons from mental health (services) and Michelle has often had the police around," Awatea Crofts told the ABC.