Late one night in March 1997, a sex worker in Vancouver's Downtown Eastside took a john up on what appeared to be a lucrative offer: ride to his farm in the nearby suburb of Port Coquitlam and have sex for $100.

Several hours later, the woman arrived in hospital with life-threatening stab wounds and carrying a knife covered in the blood of Robert Pickton.

The woman, who can be referred to only by the pseudonym Ms. Anderson, is expected to testify as early as this week at a public inquiry into the Pickton case. Anderson was initially scheduled to appear on Tuesday, but late Monday afternoon, the commission announced her testimony may be postponed.

Anderson is expected to tell the hearings about her harrowing visit to the Pickton farm 15 years ago and what happened when prosecutors later declined to put the pig farmer on trial for attempted murder.

That attack has become a symbol of everything that could have been done differently as women vanished from the Downtown Eastside in the 1990s and early 2000s, raising the devastating question of how many lives could have been saved, but weren't.

Anderson was attacked in March 1997, and prosecutors decided in January of the following year to stay charges against Pickton, including attempted murder and forcible confinement.

Two dozen women later connected to Pickton's farm disappeared between March 1997 and Pickton's arrest in February 2002, including 19 who vanished after the Crown's decision to stay the charges in January 1998.

And after Pickton's arrest in 2002, forensic investigators found the DNA of three missing women on evidence seized after the 1997 attack, including clothing and a condom package.

Anderson testified at Pickton's preliminary hearing, but her story was never told to the jury at Pickton's trial. The details were banned from publication until August 2010, when Pickton lost his final appeal on six convictions of second-degree murder.

She testified that Pickton picked her up in Vancouver and drove her to his farm in Port Coquitlam.

After they had sex, Pickton slipped a handcuff onto one of her wrists, she testified. She grabbed a knife and slashed him across the neck and arm. Pickton managed to stab her before she ran outside and down the road.

A couple driving past noticed Anderson, picked her up and brought her to hospital, where she was treated for injuries so severe that her heart stopped twice on the operating table. She was still holding the knife when she was picked up, and the handcuff was still on her wrist.

Pickton arrived later at the same hospital and a key was found in his clothes. It matched the woman's handcuff.

The RCMP in Port Coquitlam recommended Pickton be charged with several offences including attempted murder, and those charges were quickly approved by Crown prosecutors.

But in January of the following year, Crown counsel stayed the charges over concerns that Anderson, who was addicted to drugs and had missed several meetings with prosecutors, would be an unreliable witness.

The ongoing public inquiry has heard from several police officers who believed Anderson was credible and would have been a compelling witness if only the police and Crown had worked harder to ensure she participated.

"It (Anderson's story) was certainly consistent with the crime scene, and, of course, she was found with a handcuff around one wrist, so the statement that she provided certainly was consistent and believable," Mike Connor, a retired staff sergeant with the RCMP, told the hearings earlier this year.

Det. Const. Lori Shenher, who was one of the first officers with the Vancouver police to investigate reports of missing sex workers, interviewed Anderson in August of 1998 as Pickton's name rose to the top of her list of suspects.

"There was nothing in my interactions with her that would have made me question her credibility at all," Shenher testified in January.

"As morbid a thought as it is, had she died, we probably would have had a slam-dunk murder conviction without her testimony."

Crown prosecutors will also testify about why they decided to drop the charges against Pickton.

The inquiry has already heard that evidence seized from Pickton after the 1997 attack sat for years in an evidence locker without being examined for DNA.

When it was finally tested after Pickton's arrest in 2002, investigators found the DNA of three missing women.

Jacqueline Murdock's DNA was found on the outside of condom packages, Andrea Borhaven's DNA was found on Pickton's boots and Cara Ellis's DNA was found in his jacket.

The inquiry heard from the civilian RCMP lab worker who testified that even if the evidence was tested sooner, investigators wouldn't have known who the DNA belonged to because they didn't have profiles of the missing women.

Pickton's arrest in 2002 set off a massive search of his farm in Port Coquitlam, where the remains or DNA of 33 women were found.

He was convicted of six counts of second-degree murder, though he once told an undercover police officer that he killed 49.