A friend of Robert Pickton's who testified that the convicted serial killer told her there were as many as six bodies buried on his farm, has died.

Gina Houston's death comes as the justices of the Supreme Court of Canada consider whether to order a new trial in the case, the worst serial murder case in Canadian history.

It's a development that could add yet another complication to any potential retrial, which would already be saddled with many if the high court rules another should be held.

Houston was extremely frail with cancer when she testified in May 2007. An online death notice has no details beyond her name, her birthday and the day of her death, April 5.

The mortuary handling her arrangements, Fraser Heights Funeral Home, would say only that there had been a request to keep the service private.

Peter Ritchie, who represented Pickton during his trial, said a transcript of Houston's testimony could be read into the record at any retrial.

But "it's not an entirely satisfactory way to advance proof," he said in an interview Monday.

"Sometimes a dry reading of a transcript makes it difficult for a jury to know if a witness is being truthful."

Houston testified she was a close friend of Pickton, that he was a kind man and that over the years of their friendship, he gave her as much as $80,000.

At one point, he offered to marry her, she testified.

But she also told court that Pickton once told her there were "one, two, three, four, five or maybe six bodies" in one of the buildings on his farm property.

Houston testified that she asked Pickton directly if he had killed women on his farm and he said no. Instead, Pickton alluded to another close friend as being "responsible."

Pickton was convicted of killing six women. He had originally been charged with killing 26 in total, but a separate trial in 20 of those cases has been in limbo while the court process churns through the original case on six counts.

Pickton's defence team argued at the Supreme Court of Canada last month that the trial judge erred when he first instructed jurors they had to render a guilty verdict if they found Pickton was the actual killer.

But after jurors returned wondering whether they could convict if they thought Pickton was only an accomplice in the killings, the judge revised his instructions, saying they could convict if they found the pig farmer was the killer or "an active participant."

The Crown has argued the judge made no errors in his instructions to the jury and if he did, they weren't big enough to have made a difference in the outcome.

And prosecutors have said that if Pickton's six convictions stand after the high court ruling, they will not pursue the remaining 20 cases as he is already serving a life sentence.