Sarah McMahon was 20 when she was last seen in November, 2000.
The truth of what happened to 20-year-old Sarah McMahon, who vanished more than a decade ago, appears more elusive than ever after a key witness into her suspected death recanted part of a crucial statement she allegedly told police last year.
Following three police investigations spanning 12 years, an inquest was launched in Perth this week in an attempt to uncover more information about what happened to Ms McMahon.
The special crime squad of the WA Police force, tasked with investigating unsolved cases, finally appeared to have unearthed new information in November 2011.
Natasha Tracey-Ann Kendrick leaves court.
A former prostitute, who had already been interviewed twice over the disappearance, changed her version of what happened the night Ms McMahon disappeared in November 2000.
Natasha Tracey-Ann Kendrick, now 50, who at the time believed she was dying from liver failure, allegedly told police she had been called to a friend's house that night and saw the body of a woman she believed was Ms McMahon.
The pair had met some weeks earlier at the same house where her friend - the homeowner - had taken on a lodger who would later be convicted of attempted murder over an unrelated case, the Coroner's Court heard.
Ms McMahon who lived with her family in Parkerville in Perth's Hills, was last seen leaving her Claremont workplace on November 8, 2000.
She had enrolled in a Bachelor of Arts at Murdoch University that year but by September had suspended her studies as she battled with depression and drug use, her sister Amanda Smith told the inquest.
She was also dealing with a difficult break-up, according to her sister.
Through the church where her parents were long-standing members Ms McMahon had secured a part-time job working in administration - she disappeared after finishing her second shift.
As she drove away from work, the last phone call Ms McMahon ever answered was from Donald Morey - a man 25 years older her senior who has since been convicted of attempting to strangle a prostitute to death, the inquest heard,
At the time, Morey was living with his boss Gareth Allen in Marangaroo - although he had a home in Chidlow he shared with this de facto partner on the weekends, the Coroner's Court heard.
In the statement Ms Kendrick recanted on Thursday, she had claimed she helped clean up Mr Allen's house after seeing a woman's body in Morey's room the night of Ms McMahon's disappearance.
Despite being played a secretly recorded conversation with her brother taken the day after she gave her statement in which she says her "conscience is clear" and she's "done something positive", she now maintains she never saw a body.
Ms Kendrick told the Coroner's Court she had been on drugs, and was "scared" and "confused" when she gave the statement to police last year.
In his evidence, Mr Allen described the entire statement as "lies" and offered to do a lie detector test to prove he never called Ms Kendrick to his house that night and that there was never a body.
He also maintains he wasn't even at home.
"I had it read to me by the coppers and I laughed ," Mr Allen said of the statement.
"I told them 'that's a beautiful story but it ain't true' "
He said Morey took Ms McMahon and her sister over to Mr Allen's house on one occasion before her disappearance and had referred to her as "his new girl," he told the court.
The afternoon Ms McMahon disappeared, Morey had asked to borrow a truck from Mr Allen to go and see "Sarah", Mr Allen said.
"That's who I presumed it was - I'm pretty sure he said Sarah or the young girl," he said.
"I imagine he hoped for sex.
"Knowing him - without a doubt."
But Mr Allen maintained he never saw Ms McMahon and could not say whether the truck was returned that night.
Several months after Ms McMahon's disappearance, Mr Allen's wife, Marta Allen, had contacted police about a black bag that belonged to Morey, which was discovered when he was in hospital for chest pains in March 2001, the Coroner's Court heard.
Mr Allen said the bag contained graphic pornography involving people "dressed up like they were dead" that he "could not even look at".
It also contained gaffer tape, rope and knives, he said.
"Marta came to me and said I need to go to the police and I told her to follow her heart," he said.
But before the police came to look at the bag - days later - Morey's partner had come and taken it away, he said.
Morey, who is currently serving 13 years jail for attempted murder, is expected to give evidence on Friday.
He has consistently denied any knowledge of what happened to Ms McMahon.
The inquest continues.