An aerial view of Robert Pickton's farm in Port Coquitlam, B.C., taken by police during their investigation in 2002. (Canadian Press)

Newly revealed court material shows that convicted serial killer Robert Pickton was charged with attempted murder of a sex-trade worker in 1997, but the case did not go to trial and he went on to kill an unknown number of Vancouver-area women.

The woman in the 1997 case — who still cannot be legally identified — alleged that she had been hired for sex by Pickton and was taken to his farm, where he tried to handcuff her and then stabbed her repeatedly, nearly killing her.

The woman suffered stab wounds to her abdomen, chest and arms, lost three litres of blood and remained unconscious in hospital for four days before recovering.

Pickton was charged with attempted murder and forcible confinement in that case, but the Crown later stayed the charges, saying the woman was not a sufficiently credible witness.

Ten years later, Pickton was convicted on six counts of second-degree murder in the deaths of six women from Vancouver's Downtown Eastside neighbourhood and sentenced to life in prison.

All six women were killed after the 1997 case was dropped.

As the Crown announced Wednesday it was staying 20 other murder charges against Pickton, ending the possibility of more trials, the court lifted the publication ban on a raft of controversial material connected to the trial that produced his conviction.

The sex-trade worker had provided riveting testimony at Pickton's 2003 preliminary hearing, but the jury at his murder trial was not allowed to hear her story.

The judge accepted a defence argument that the woman's testimony was not directly relevant to the six charges Pickton faced.

The lifting of the publication bans also means that Pickton's videotaped statement to police after his arrest will be released within a few days.