The brother of Robert William "Willie" Pickton says he had no idea sex workers were being taken to his family's property near Vancouver and murdered, and he denies ever helping the serial killer cover up his crimes.

The children of several women whose remains or DNA were found on Pickton's property in Port Coquitlam, east of Vancouver, filed lawsuits last year against Pickton, Pickton's brother David, and the police.

David Pickton has now filed statements of defence, denying any knowledge of what his brother was doing and rejecting the families' claim that he should be held liable for the women's deaths.

Serial killer Robert Pickton was convicted on six counts of second-degree murder, but is suspected of killing dozens of women who went missing from Vancouver's Downtown Eastside. (Vancouver Police Dept)

"William's criminal acts were not known to David, nor were they reasonably foreseeable to him," says one of seven identical statements of defence filed this week.

"Any offences committed by William were on the property solely occupied by William Pickton."

The families' lawsuits also allege David Pickton lied to police after Robert Pickton was accused of attempting to murder a sex worker in 1997. That case did not proceed to trial.

"David Pickton did not aid or abet William Pickton's alleged attack in on the '1997 victim,"' says the statement of defence. "David Pickton did not assist William Pickton in 'getting away' with any offence."

9 families launch civil suits

The families of nine women have filed lawsuits, but only seven of those cases name David Pickton as a defendant. He also filed a statement of defence this week in an unrelated lawsuit in which he is accused of sexually assaulting a woman in the early 1990s.

All of the court documents contain allegations that haven't been tested in court.

David Pickton has always been on the periphery of his brother's case, but he has never been formally accused or charged with anything connected to Robert Pickton's crimes.

The Pickton brothers and their sister, Linda Wright, own the infamous property in Port Coquitlam where Robert Pickton lived in a run-down trailer and where police found the remains or DNA of 33 women. The siblings inherited the property from their parents.

David Pickton's name also surfaced several times during the public inquiry that began in late 2011 and stretched well into 2012.

The inquiry heard evidence that when police attempted to interview Robert Pickton in September 1999, David Pickton asked investigators to wait until the rainy season was finished. The officers agreed and didn't interview Robert Pickton until January 2000.

Robert Pickton filed his own statements of defence last month, denying all of the allegations but offering no details.

After Robert Pickton was convicted of six counts of second-degree murder and sentenced to life in prison, he made statements to various media outlets claiming that others committed the crimes. (Canadian Press)

Government lawyers acting on behalf of the Vancouver police and the RCMP filed statements of defence last fall, insisting their officers acted reasonably as they investigated reports of missing sex workers in the late 1990s and early 2000s.

Both forces have publicly apologized for not catching Robert Pickton sooner.

He was convicted of killing six women.

2nd lawsuit on unrelated sex assault

Meanwhile, David Pickton has also filed a statement of defence in an unrelated lawsuit involving sexual assault allegations that date back more than two decades.

The woman's statement of claim, filed last November, alleges Pickton sexually assaulted her on a job site in August 1991. The lawsuit alleges that when the assault was interrupted, Pickton threatened to rape her, and later threatened to kill her.

The lawsuit says Pickton was convicted of the sexual assault in Burnaby provincial court in February 1992.

In his statement of defence, Pickton denies all of the allegations. Instead, he accuses the woman of breaking into a trailer in a robbery attempt.

"She was 'caught in the act' by the defendant, who told her to leave," the document says.

"The defendant administered the minimum amount of force required to expel her. The defendant specifically denies any unlawful assault. ... The defendant at no time threatened the plaintiff."

When contacted about the lawsuit last fall, Pickton said he couldn't remember if he was convicted of sexual assault in 1992, as the woman's lawsuit claims.