A new documentary alleges that serial killer Robert Pickton's inner circle knew key details relating to his crimes, but their dependency on Pickton kept them from going to police.

In the wake of his conviction in 2007 -- and the subsequent lifting of the publication ban on the case last month -- "The Pig Farm" aims to explain why Pickton was able to continue killing for years before police finally apprehended him.

Writer and producer Christine Nielsen said the documentary shows that Pickton's "inner circle, the people who hung out at the farm with him, the people who worked with him, who were his friends," knew things early in his murder spree but never reported them to authorities.

"One of the key things that maybe hasn't come out in a lot of the media is Pickton was pretty cagey," Nielsen told CTV News Channel. "He played white knight to the down-and-out. So these people felt beholden to him in many ways. And some of them just thought it was easier to just say nothing, or they thought that by saying nothing they could keep financing their drugs and their lifestyle."

"It's very hard to imagine," she added, but many of Pickton's closest associates were "so down and out, so addicted, so dependent" that they never reported what they knew about Pickton's activities.

"Virtually all" of the people who were close to the serial killer during his years-long rampage appear in the documentary, Nielsen said.

One is a woman who says she escaped from Pickton's farm after he tried to kill her in March of 1997. The two got into a knife fight and were both injured, the woman says, before she staggered off the farm and was picked up by a passing driver.

Pickton faced attempted murder charges in connection with the alleged altercation, but those charges were later stayed.

He was eventually taken into custody in 2002. In the meantime another 13 women disappeared, and investigators later found DNA from 11 of those women on Pickton's infamous farm.

Pickton was finally charged with murdering 27 women, and was convicted on six counts of second-degree murder. The B.C. government announced this week it would launch a public inquiry into how police handled the case.

"The Pig Farm" airs Saturday at 9 p.m. on CTV (check local listings).