OTTAWA - There is no doubt in the mind of Canadian author Stevie Cameron that serial killer Robert William Pickton is the man responsible for more than two dozen murders in Vancouver.

Nor is there doubt in her mind that police could have caught him much earlier than the day in 2002 that they finally arrested the former pig farmer for five years of a brutal killing rampage.

But even after following the case for more than 10 years and writing two books about it, Cameron says there is still much she doesn't know.

A public inquiry is necessary, she said.

"What I don't know, despite all my charts and chronologies and transcripts, I don't know what the police know," she said.

"None of us know what the police know."

In her latest book, called On the Farm: Robert William Pickton and the Tragic Story of Vancouver's Missing Women, Cameron draws extensively from exclusive interviews from voices never heard during the massive police investigation and subsequent trial.

The electronic version of the book was published Saturday with a hardcover expected by the end of the month.

Pickton was charged with 26 counts of first-degree murder. He stood trial on only six because the judge decided a trial on all the charges was too much for a jury to bear.

Once the Supreme Court upheld the conviction on six counts of second-degree murder, the remaining charges were stayed. Six other potential charges were also set aside.

The book is a major departure from Cameron's previous books on Canadian politics and business, including one on the relationship between former prime minister Brian Mulroney and a German businessman named Karlheinz Schrieber.

Her first journalistic look at the Pickton trial came in 1998 when she assigned a story on Vancouver's missing women to one of the reporters at Elm Street Magazine, where she was the editor.

Much like the public and police at the time, the reporter wasn't interested in exploring the harsh nooks and crannies of the Downtown Eastside, but after three days looking into the story, he was captivated and so was she.

When Knopf Canada approached her in 2002 to write a book on the case, she immediately said yes.

"It was a huge release, because the people I normally write about never go to jail and I figured this guy might actually go to prison," she said.

She wrote her first book on the case in 2007, a personal look at being involved in the trial.

The second is 750 pages, a mix of testimony given in preliminary and trial hearings and interviews Cameron conducted on her own, many set up by the families and social support workers who'd come to know the women and the world of Willie Pickton.

The story begins in his world, as she unpeels Pickton's life by talking about a childhood filled with poverty and torment, an adolescence where he could never quite fit in and then adulthood where he fought to be his own person.

He was far from the stupid and docile character painted by the defence at his trial, Cameron suggests.

In story after story, a woman who was close friends with Pickton describes a methodical, paranoid and extraordinarily private man who ran his own personal and business life as far away from his family as he could get.

Lisa Yelds was the woman who helped Pickton recover from a fight with a woman he'd picked up, and tried to handcuff in 1997. That woman fought back, slashing at him before running out into the road.

"I always had this thought at the back of my mind that Willie could be a serial killer," Yelds tells Cameron in the book, "but I was never afraid of him myself. I knew he would never hurt me."

While in police interviews Pickton professed delight at becoming infamous, Cameron said the goal of the book wasn't to glorify him.

His childhood, Cameron said, was a breeding ground for resentment and rage.

"He is the biggest creep I've ever seen but certainly telling the back story of his family is necessary," she said.

Cameron says she believes that Pickton, who has refused to formally admit his guilt in any of the murders, could one day tell his own story of what happened, especially because he likes attention.

"A profiler might be able to go in and talk to him," she said.

Police routinely ignored the assistance of profilers for years on the case, as Cameron documents in the book.

She said the story of Roy Hazelwood, one of the most famous profilers in the world, is one of the most telling. Hazelwood was brought in before police began their interview with Pickton after his arrest.

"They bring him up there and he says don't appeal to (Pickton's)

conscience, don't try and make him feel terrible about this,"

"(The officer) marches right in and says think of your mother up in heaven Willie, and Pickton looks at him like he crawled up from under a rug."

Among the horrors that Pickton wrought on the women of Vancouver's Downtown Eastside was deep feelings of guilt among those who did not end up becoming his victims.

One of them opened up to Cameron, explaining why she thought she lived.

Pickton picked up Tracey Bulan in 1996.

Bulan says after they had sex, Pickton came at her with a knife and accused her of having his wallet. She walked out of his trailer and he came after her a few minutes later and drove her back downtown.

She says Pickton picked on the worst-off women in the neighbourhood, making friends with them and winning their trust by promises of helping them get clean.

But he only gave them one chance: "if they go back to dope, well then, they don't deserve to live. They're useless. They're better off dead."

Bulan survived, she tells Cameron, simply because she wasn't high.

Cameron said she doesn't think Bulan was interviewed by police, even though she was the one who first put Pickton on the bad date sheet.

While a public inquiry may be announced, and a police review of how they handled their case soon to be public, the story is now coming to an end, Cameron said.

Former witnesses have died, others remain terrified of the Picktons and have moved away. The public may also just not have the heart to hear any more, Cameron said.

"You never get the whole story," she said.