VANCOUVER -- The British Columbia government says it can't be sued over the decision of Crown prosecutors to stay attempted murder charges against Robert Pickton in 1998 -- four years before the remains of dozens of women were found on the serial killer's farm, including many who vanished after he was accused of trying to kill a sex worker from Vancouver.

The families of four women whose remains or DNA were found on Pickton's property filed a lawsuit in May targeting the provincial and federal governments, the City of Vancouver, Pickton's siblings and Pickton himself.

The provincial government has filed an application in B.C. Supreme Court asking that the allegations targeting B.C.'s criminal justice branch be removed from the statements of claim.

The lawsuits allege, among other things, that prosecutors were negligent when they decided not to put Pickton on trial for attempted murder in early 1998. The lawsuits also claim the Crown should have warned sex workers in Vancouver about Pickton in light of the attempted murder charge.

But the B.C. government's notices of application say Crown lawyers are immune from most claims of negligence, unless there is clear evidence of "deliberate and malicious" conduct.

"The notice of civil claim in this case includes no pleading of malice on the part of the Crown counsel involved," says one of four notices filed with the court last week.

"This is clearly not a claim of malicious prosecution. It is therefore plain and obvious that it has no reasonable chance of success."

The notices also argue Crown prosecutors don't have a duty to warn the public.

In March 1997, Pickton and a sex worker became entangled in a violent confrontation at his property in Port Coquitlam, B.C., leaving the woman with injuries so severe she died on the operating table before she was revived.

The sex worker, whose name remains covered by a publication ban, had a set of handcuffs locked on one of her wrists -- the key to which was later found in Pickton's pocket.

Days before Pickton was set to stand trial, a Crown prosecutor decided not to go ahead. Crown counsel Randi Connor told a public inquiry last year that she believed the sex worker's drug use meant she wasn't in a condition to testify.

Between January 1998, when the charges against Pickton were stayed, and his arrest in February 2002, 19 women disappeared and were later connected to Pickton's farm.

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

The lawsuits involve the daughters and sons of Dianne Rock, Sarah de Vries, Cynthia Feliks and Yvonne Boen.

The statements of claim allege the Vancouver police and the RCMP botched their respective investigations into missing sex workers from the Downtown Eastside and failed to warn women in the neighbourhood that a serial killer was likely at work.

Boen's and Feliks' children also allege they were harmed by the insensitive manner in which they were informed of their mothers' deaths.

Pickton was eventually convicted of six counts of second-degree murder.

When Pickton lost his appeals for those convictions, charges related to the murders of 20 other women, including Rock, de Vries and Feliks, were stayed by the Crown. Boen is among six women whose remains or DNA were found on the Pickton property but for which no charges were ever laid.

The statements of claim contain allegations that haven't been tested in court.

None of the defendants have filed statements of defence, and the province's recent notice of application makes no mention of any of the other allegations in the families' lawsuits.