A police manhunt is under way for 19-year-old Perth man Ross James Boag over the death of mother-of-three Peta Fairhead who was dumped outside a hospital.
Two other men aged 19 and 20, faced Joondalup Magistrates Court on Friday on charges of murdering 27-year-old Ms Fairhead.
It is alleged Lucas James Yarran, 20, and Leroy Daniel Smith, 19, stormed a home in Perth's north armed with a baseball bat and machete, and kidnapped and murdered Ms Fairhead and stole jewellery and methamphetamine.
They are accused of afterwards pushing Ms Fairhead out of a car with significant injuries and leaving her to die outside the emergency unit of Joondalup Hospital about 3.15am on Wednesday.
Detectives believe Boag can assist them with their investigation and have appealed for public help in finding him but say he should not be approached.
He is described as about 172cm tall, with fair skin, a medium build, short red hair and blue eyes, and frequents the Joondalup area.
Yarran and Smith face seven charges, including armed robbery, kidnapping and murder.
They are yet to offer a plea and were remanded in custody to appear in Stirling Magistrates Court on August 31.
Ms Fairhead moved to Perth from the Wheatbelt town of Quairading this year.
