Families of Robert Pickton's victims say they're relieved there will be a public inquiry into the botched police investigation that allowed him to continue killing sex workers for years.

"I'm feeling very happy," said Liliane Beaudoin, whose adoptive sister Dianne Rock was suspected to have been among the serial killer's victims, though the outstanding murder charge was stayed.

"We're hoping this inquiry will bring significant changes that better the system for the women, and are beneficial to assisting the police in helping the women off the streets," Beaudoin told CTV's CanadaAM from Welland, Ont. on Friday.

B.C. Attorney General Mike de Jong said Thursday the province will launch an inquiry with the power to compel testimony from witnesses. He would not say when the process will begin, or who will oversee the commission.

"There are still lingering questions about the nature of these investigations, questions about whether more could have been done sooner, are we in a position to learn from the investigations and mistakes that may have been made," he told reporters Thursday.

"The government has taken the view that the best vehicle by which that can be accomplished is a public inquiry."

Families and friends of women who disappeared from Vancouver's Downtown Eastside have long pushed for a public inquiry. Many have accused police of brushing off their concerns when they reported the women missing.

Pickton was arrested in 2002. A massive search of his Port Coquitlam farm revealed the remains or DNA of 33 women. He was charged with killing 27 women and later convicted of six counts of second-degree murder.

The convictions were upheld by the Supreme Court of Canada in July. Prosecutors have said they would not file any further criminal charges against him.

The conclusion of the criminal case renewed calls to examine how police handled the file.

An internal review of the investigation released by Vancouver police last month listed a series of missteps by both the Vancouver force and the RCMP.

The report found that authorities failed to properly share information regarding the case, that they lacked leadership and that some Vancouver police officers were prejudiced against the women, many of them sex workers.

The document accused the RCMP of neglecting the investigation and mishandling an interrogation of Pickton in 2000, two years before he was finally arrested.

The RCMP has prepared a similar report, but it has not yet been released.

With files from the Canadian Press