The former driver of murdered Perth madam Shirley Finn has revealed compelling new details about the brothel owner's relationship with then police minister Ray O'Connor, who went on to become WA's premier.

Key points: Driver claims former police minister Ray O'Connor had affair with Shirley Finn, despite denials he ever met her

Driver claims former police minister Ray O'Connor had affair with Shirley Finn, despite denials he ever met her Witnesses previously too scared to talk expected to give evidence at inquest

Witnesses previously too scared to talk expected to give evidence at inquest Allegations persist police, politicians played role in Finn murder

In an interview with Australian Story, Leigh Beswick confirmed long-standing rumours Finn was in a relationship with O'Connor.

"I used to drive them up to Kings Park and take them to the Swan River. Nine times out of 10 they'd have a bottle of wine. They were having a great old time," Mrs Beswick said.

O'Connor, who died in 2013, consistently denied having met Finn and said suggestions otherwise were "a joke".

Finn was murdered just three days before a tax hearing, at which she was threatening to blow the whistle on illicit dealings by politicians, businessmen and police.

Shirley Finn was murdered just three days before a tax hearing as she faced a $100,000 debt. ( Supplied )

According to Mrs Beswick, Finn had warned O'Connor of her intentions unless he helped her deal with a $100,000 tax debt.

"I know she went to him and asked him for help. The conversation I heard between Shirley and Ray O'Connor was 'if I go down you go down'," Mrs Beswick said.

Finn was allegedly paying kickbacks to senior detectives under the police "containment" system, which allowed police to determine who could run brothels in Perth and how.

Rumours of police involvement in the murder have been rife from the outset.

O'Connor was jailed in 1995 after misappropriating a $25,000 donation to the Liberal Party from the Bond Corporation.

Chilling murder with a macabre twist

Finn was last seen by a neighbour as she was leaving her home in a "glittering gown" at 9:40 pm on Sunday, June 22, 1975.

According to an acquaintance of Finn, named Jacqueline [surname withheld], she had been on her way to a meeting with an "important person" who could help her with her tax problems and had been told by a senior police officer to "dress to impress".

The following morning, Finn's body was found slumped in her Dodge, four bullet holes in her head, at Royal Perth Golf Course.

Shirley Finn was found in her Dodge car with four bullet holes to her head. ( Supplied )

She was wearing a full-length ball gown.

There was little doubt Finn had been professionally executed in what was known as a "bowling ball execution".

The first reporter on the scene, television journalist Terry Willesee, has been haunted by the memory of what he saw that day.

"I walked over to an American sedan and I saw the body of a woman. This magnificent gown she was wearing still sticks in my memory today," he said.

Police recovered a bullet cartridge from the back seat of Finn's car but the murder weapon was never found.

The original police investigation ended after less than a year. Two cold case inquiries in 2005 and 2014 failed to find the killer.

Daughter tormented by 'failure to fully investigate'

Sorry, this video has expired Shirley Finn's daughter, Bridget Shewring says it is time she had answers as to who killed her mother.

Although Finn's daughter, Bridget Shewring, was only 12 years old when her mother was murdered, she remembers the day clearly.

"I was in first period social studies and the headmistress came in and asked for me. She wrapped her arms around me and said, 'I don't know how you are going to live through this Bridget'," Ms Shewring told Australian Story.

Ms Shewring said she heard little more about her mother until 2004, when she was contacted by author and journalist Juliet Wills.

Shirley Finn was found slumped over in her car wearing a full-length ball gown. ( Supplied: Bridget Shewring )

Wills had begun investigating the case and was shocked by "the level of corruption" she had discovered.

"I told Bridget I believed there had been an incredible wrong and police had attempted to cover up the murder of her mother and that I was determined to get to the bottom of it," Wills said.

Over the next decade, Wills conducted interviews with dozens of witnesses, including a retired police officer who claimed to have seen Finn on the night she was murdered, in the police canteen with two detectives.

"When he learned of the murder he went straight to senior officers to report what he'd seen," Wills said.

"He said that the next day he was knocked off his motorcycle, had a gun held to his head and was told to shut his mouth or he'd be killed."

Officers inspect the scene at the Royal Perth Golf Course where Shirley Finn was found dead in 1975. ( Supplied )

Wills handed interviews she had conducted to police but has been disappointed by what she described as their inaction.

"This is possibly the highest level politically sanctioned murder in the history of Australia but they just weren't willing to delve further," Wills said.

Ms Shewring and Wills first sought an inquest in 2005, only to be told there was insufficient evidence.

However, last year, after the Special Crime Squad reviewed the case and after significant new evidence was presented to them, an inquest was granted.

In a statement to Australian Story, a WA Police spokesperson said: "The Commissioner welcomes the forthcoming coronial examination of this case especially if it can help resolve the matter."

In 2015, Western Australian Police Commissioner Karl O'Callaghan said he "would like nothing better" than to be the police commissioner who resolved the Finn murder.

Shirley Finn had three children — Shane, Bridget and Steven. ( Supplied )

Plea for witnesses to come forward

Although time is not on her side, Ms Shewring believes there is still information to be found.

"We have been told in the past that it's hopeless but we have had three significant new witnesses come forward in the past two years," she said.

One of those witnesses, Jacqueline, has been too scared to talk publicly until now.

She saw Finn just days before her murder and said the brothel owner feared for her life.

She agreed to be interviewed on Australian Story to encourage other witnesses to come forward at the inquest to be held later this year.

"I am looking forward to going to the inquest and telling what I know and speaking about what happened. I just hope that others do the same," she said.

Watch Australian Story's "Getting away with Murder" tonight 8pm (AEST) on ABC TV.