An inquest into the 1975 gangland-style murder of Perth brothel madam Shirley Finn is set to begin amid ongoing speculation of police involvement, or a cover-up.
Ms Finn was wearing a ball gown and sitting in her parked car near the freeway in South Perth when she was shot four times to the head at close range in June 1975.
She was being investigated by the tax office over a $100,000 bill and had threatened to name people she had been involved with, or paid kickbacks to.
A new investigation into her death was launched in 2014 following a cold case review but did not result in any charges being laid.
Rumours have persisted about the case, with an investigator at the time of the murder linked to NSW corrupt cop and convicted killer Roger Rogerson.
Author Juliet Wills said a retired Western Australian policeman broke his 40-year silence to reveal in her book that Ms Finn was at a police station shortly before her murder.
The man, known only as Brian, alleged he had just finished his shift as a traffic officer when he saw two detectives walk in with two well-dressed women.
He realised it was Ms Finn after her murder but was threatened against speaking up.
Former Liberal WA premier Ray O'Connor, who was jailed for six months in 1995 as part of the WA Inc scandal and died in 2013 aged 86, denied ever meeting Ms Finn, but her driver Leigh Beswick told Australian Story they were close.
Ms Finn threatened to take Mr O'Connor "down" with her three days before her murder, when he was the police minister, Ms Beswick said.
The inquest, which Ms Finn's daughter Bridget Shewring has long campaigned for, is scheduled to run for two weeks.