Robert Adams found guilty of the murder of nurse Mary Wallace in 1983

Nurse Mary Louise Wallace was on a night out with friends on Sydney's lower north shore when she made the fateful decision to get into a car with a man who pretended to be a police officer. 

Ms Wallace, who worked as a nurse at Hunters Hill Private Hospital, was last seen by friends leaving the Alpine Inn wine bar at Crows Nest about 4am on September 24, 1983. 

Guilty: Robert John Adams arrives at the NSW Supreme Court with his legal representatives. Photo: James Alcock

On Friday, more than 33 years after her disappearance, the man she accepted a lifted home with - convicted rapist Robert John Adams - was found guilty of her murder. 

Adams, 64, has been a free man until now - walking in and out of court for the duration of his judge-alone trial before Justice Richard Button in the NSW Supreme Court. 

He crossed his arms and appeared emotionless as the guilty verdict was read out. 

Justice Button found that Adams raped and strangled Ms Wallace before disposing of her body, which has never been found.

Before delivering his verdict, Justice Button found beyond reasonable doubt that Adams had raped and tried to strangle three women in the lead-up to Ms Wallace's murder.

"Each woman was treated as nothing more than an object," Justice Button said. 

Nurse Mary Louise Wallace was last seen getting into Robert Adams' car in September 1983.  Photo: NSW Police

"The accused had a tendency to rape and strangle women."

Adams, a carpenter who worked at the Lane Cove National Park, was originally arrested in September 1983.

Officers from the Unsolved Homicide Squad were finally able to charge him with murder in 2013 after two hairs collected from the boot of his Holden Commodore were matched with hair found on Ms Wallace's hairbrush.

Adams has always denied murdering Ms Wallace, claiming that he drove her away from the Crows Nest bar and pulled his car over near Willoughby Road where the pair started "playing" sexually with each other. 

He said that, at some point, he passed out and that, when he woke up, Ms Wallace had vanished. 

When police asked Adams, during an electronically recorded interview after his arrest, whether he had sexual intercourse with her, he said he could not remember.

"I know my little fella was out, that was about it, I think. Oh I remember playing with, with her, you know, and then just, that was it for a while," he said.

He then drove to his Chatswood apartment before attending a champagne breakfast at St Leonards.

During the police interview, he said that, on the afternoon of Monday, September 26, he stayed home and washed both his car seats because the passenger seat "had 'come' on it and it smelled".

The court heard from three women who had been choked and raped by Adams before Ms Wallace's murder. 

Adams showed no emotion during their evidence, and often cleaned his glasses, chewed on gum and did word puzzles in the dock. 

Adams had previously been convicted of raping a woman he met at the Middle Harbour Yacht Club.

This woman told the court how she had agreed to get into his car. Then he pulled over, put his hands around her throat and began to choke her.

The court heard he said to her: "I'll f--- you either dead or alive."

And later: "Either f--- me now or I'll f--- you when I kill you."

Adams raped the woman after threatening to "finish her off" and throw her in the river if she did not do what he wanted.

Adams made further admissions to police during the interview, telling officers that he and his friends played a game whereby they would score points for bedding women. 

The trio would pretend to be pilots, barristers, police and even "football stars" to see how many women they could have sex with on a weekly basis.

"That's what everybody did ... it was a contest for, between us, who could get laid the most and we sort of bragged about it and, you know, we just sort of, you know, couldn't say I was a silly old carpenter, could I? Doesn't sound exciting," he told police.

"I was a sleazebag then and to get a lay, it was, you know, it was the purpose of getting laid and you just told a pack of bullshit to get laid," he said.

Outside court, Ms Wallace's close friend Pauline Biddle Broadfoot said, "I think it's fantastic what they've done - it's real closure."

Family members were in tears, hugging one another.