VANCOUVER - A combination of the law, police tactics and bad attitudes among officers has forced street-level sex workers out of sight where they are easy prey for predators such as Robert Pickton, a prostitution expert told the public inquiry into the serial killer's case on Thursday.

John Lowman said police in Vancouver have engaged in a decades-long campaign to move prostitutes out of residential neighbourhoods and upscale areas of the city and into the industrial and commercial areas of the Downtown Eastside, where Pickton spent years hunting his victims.

That eventually meant sex workers were in isolated areas out of sight of both police and local residents, making it easy for predators to target the women with impunity, said Lowman, a criminologist at Simon Fraser University.

"When women are spread out in an area like that in back alleys and pushed off the main streets, they're a much easier target for a misogynistic predator pretending to be a client," Lowman, the first witness at the hearings, said during his testimony.

"I don't think it was the intention of anybody to make this a more dangerous area or the situation worse, but I think that's exactly what it did."

Commissioner Wally Oppal is examining why the Vancouver police and the RCMP failed to catch Pickton as he murdered sex workers from the Downtown Eastside in the late 1990s and early 2000s, as well as the decision by Crown counsel not to prosecute Pickton for attempted murder after an attack in 1997.

Lowman said a number of factors converged to make life for impoverished, drug-addicted street prostitutes, many of them aboriginal, particularly dangerous by the time Pickton began bringing them to his farm in nearby Port Coquitlam to be butchered.

Under pressure from the city and residents, Vancouver police spent years displacing street-level sex workers away from residential areas — even those in the Downtown Eastside itself — into the deserted, poorly lit and scarcely policed industrial areas nearby. Sex workers knew if they stayed in such areas, which served as unofficial red-light districts, they could reduce the chance they'd be arrested, he said.

At the same time, local courts were imposing conditions on sex workers ordering them to stay off the main strolls in the Downtown Eastside, forcing them to side streets or back alleys, where they were even more isolated.

And Canada's prostitution laws encouraged police to view sex workers primarily as criminals, making it more difficult for prostitutes to come forward if they were abused, and fostering dismissive attitudes among some officers, Lowman said.

Lowman has interviewed sex workers during his research who recalled being ridiculed by police officers when reporting assaults, and harassed while on the streets. For example, some sex workers were taken on "starlight tours," in which officers drove them across the city and dropped them off with little way to find their way back, he testified.

"The law itself encourages an adversarial relationship between street-involved women and the police," said Lowman.

He said that reality exposed sex workers to people like Pickton, who appeared to have picked up women from the Downtown Eastside with a plan to kill them from the outset.

Lowman said Pickton fits the description of a classic predator, which he described as a man who hates women and poses as a client to attack or kill sex workers. Lowman contrasted that with a client who might attack a sex worker in the heat of the moment during a sexual encounter.

"In your opinion, Pickton would have planned ahead of time in a premeditated manner and formed that intent at the time he was picking up the woman?" commissioner Wally Oppal asked Lowman.

"The likelihood that he may have done that five times or 10 times or 49 times, the idea that he didn't premeditate it sounds rather unlikely to me."

Pickton was arrested in 2002 and eventually convicted of six counts of second-degree murder. The jury declined to convict him on the more serious charge of first-degree murder. He was sentenced to life in prison with no parole for at least 25 years.

The remains or DNA of 33 women were found on Pickton's farm, though he boasted to police that he killed a total of 49.

The inquiry's terms of reference focus specifically on the actions of police and prosecutors, but a number of advocacy groups have urged Oppal to look at broader issues affecting sex workers in the Downtown Eastside such as poverty, drug use and prostitution laws.

Lowman's testimony alternated between discussing how police in Vancouver treat sex workers and debating the actual law — two areas that he said were intertwined. Lowman has publicly advocated for decriminalization.

He became emotional at one point, breaking down in tears when asked what changes need to be made to protest sex workers from violence.

"We have to find solutions to poverty, the feminization of poverty. We have to find solutions to addiction. We have to find solutions to the effects of 200 years of colonization on West Coast aboriginal people. We need to rationalize our prostitution law so that we understand what it is that it's trying to do," he said.

"If people are going to be involved in prostitution, until we solve those other issues, we could see very similar things happening in the future."

Later, Lowman was asked why he lost his composure.

"I'm frustrated," he said. "We're talking about extreme human suffering and it got to me."

Oppal is also conducting a less-formal set of hearings known as a study commission to examine broader issues surrounding missing women, including the so-called Highway of Tears in northern B.C.