A B.C. court will soon hear an exceptional argument: that police on Vancouver Island were guilty of entrapment in an undercover investigation targeting child sex predators online.

Pai-Chih Chiang was convicted of communication for the purposes of obtaining sex from an underage person in B.C. Supreme Court on June 4, after he responded to an "erotic services" ad on Craigslist.

On Monday, his lawyer Michael Mulligan will ask for a stay of proceedings in the case. He is expected to argue that Saanich police entrapped Chiang, convincing him to buy sex from an underage girl when he was really looking for the services of an adult woman.

In the spring of 2009, the department placed an ad on Craigslist advertising "Sexy, young tight bodies lookin for fun."

The ad was part of a one-time campaign that began with a complaint from a parent, according to Const. Andy Stuart, one of two officers in charge of the operation. A local woman had complained that her underage daughter was advertising sex for sale online.

Stuart's team came up with a strategy after speaking with other police departments across the province, but his approach was a new one.

"I don't think any other police department has tried this at that point," he told ctvbc.ca.

'She's only 16?'

The Craigslist ad showed a fully developed woman from behind. In his decision convicting Chiang, Judge David Harris wrote that there was nothing in the photograph to indicate whether the woman was an adult or an underage girl.

Chiang was one of dozens of men who responded to the ad on April 14. He emailed to ask for 30 minutes of "FS": online shorthand for full-service sex.

After a 15-minute exchange, police officers using the email address "freshtna16@gmail.com" gave Chiang a choice: "We have 2 girls Janelle 16 and Courtney 17 which do you prefer?"

Chiang asked for pictures.

As Harris wrote in his ruling, "Neither picture would allow anyone to draw a conclusion that either woman was under 18. Equally, neither would exclude the possibility. In fact, as is common ground, both individuals were over 18 and the person posing as Janelle, who was herself a police officer, was about 30 years old."

After looking them over, Chiang decided on Janelle, and agreed to meet at the Accent Inn on Blanshard Street in Saanich in less than an hour.

He showed up on time, with $150 in hand, to meet "Mckenzie," an undercover officer disguised as a madam, in the hotel's parking lot.

She told him that there would be a few ground rules for the encounter: "Because Janelle is only 16, there can be no rough play, or rough sex, or anything like that."

In court, the undercover officer said that Chiang looked shocked as she told him that.

"She's only 16?" he asked.

"Well yeah, I told you that on the email," Mckenzie replied.

"I thought that was just a number. I didn't know," Chiang said.

Mckenzie assured him everything was "cool," and that Janelle was eager to please.

"Yeah, but is that alright?" Chiang asked.

Mckenzie admitted that the girl was under the legal age, but told him: "There are 16-year-olds walking the streets. At least this way we are trying to protect them as best we can."

After a short conversation about pricing, Mckenzie asked Chiang if he was in.

"Yeah, I'll check it out," he said.

He got out of his car and went to the door of the room where Janelle was supposedly waiting. Instead, he found a crowd of police officers, and was arrested on the spot.

Reasonable doubt?

Since that day, Chiang has lost his job and is allowed only supervised visits with his children.

During his trial, defence lawyer Michael Mulligan argued that the Crown hadn't proven beyond a reasonable doubt that Chiang was looking to buy sex from a 16-year-old. When he said "I'll check it out," he might have meant that he wanted to confirm Janelle's age by sight.

But Judge Harris dismissed that argument, writing, "There is nothing to suggest that what he is going to ‘check it out,' if the phrase is taken to mean that he is going to ascertain more information, is that Janelle is over age rather than, for example, sufficiently appealing for him to complete the transaction."

Both Chiang and his lawyer declined to speak to ctvbc.ca about the judge's decision, and about the entrapment argument set to be heard on Monday.

A complex and rare argument

Const. Andy Stuart of the Saanich Police Department said he will testify at the hearing in Victoria at B.C. Supreme Court.

While he wouldn't comment on how Canada's entrapment laws apply in the case, Stuart told ctvbc.ca that the majority of men who appeared at the Accent Inn on April 14 drove away when they learned that the "girls" they were meeting were underage.

Forty-two men showed up at the hotel, but only two were arrested: Chiang and Norman Sedore, whose trial is scheduled to begin in the fall.

"Most of them said, ‘No thanks, too young,'" Stuart explained. "People did turn away."

Vancouver defence lawyer Terry LaLiberte told ctvbc.ca that entrapment arguments are uncommon in Canada.

"This is a very complex argument," he said. "It's based on the notion that limits should be imposed on the ability of police to participate in the commission of the offence."

In the very rare cases when defence lawyers argue for a stay of proceedings because of entrapment, they tend to accuse police of conducting what are known as random virtue tests.

"They go beyond providing an opportunity and actually induce the commission of an offence," LaLiberte explained.

Police have every right, legally speaking, to go undercover and present criminal opportunities, but only as long as they're targeting either a person or a place suspected to be connected to that criminal activity.

In the Saanich sting, police would have two options to justify their undercover operation.

First, they could prove that they had reason to believe that Chiang -- who has no previous record beyond a few speeding tickets -- was already engaged in trying to buy sex from underage girls.

Or, more likely, they'd have to prove that their undercover operation targeted a place where sexual predators regularly try to buy sex from underage girls.

Although LaLiberte is not involved in the case, he predicted that the judge's ruling will hinge on, "whether or not Craigslist is a place that's being utilized to advertise underage sex."

The site's "erotic services" section has been connected to crime in the past, and no longer exists in the U.S.

After a masseuse who advertised on Craigslist was murdered last year, the site's developers decided to eliminate the section and screen all new submissions into a new "adult services" section before they are posted.

A landmark case

Whatever the judge decides, police departments across the province will be watching Monday's hearing with interest.

Both the Vancouver and New Westminster police departments have been conducting undercover online operations targeted child sexual predators for years, but neither department has ever been accused of entrapment.

Although there are few, if any, examples of entrapment arguments aimed at B.C. cops conducting undercover online child sex investigations, one recent ruling in Alberta might set a precedent useful for the Chiang case.

A Calgary cop on trial for child luring asked for a stay of proceedings in his trial in May, arguing that his fellow police officers entrapped him when they posed as a 17-year-old girl online.

In that case, Const. Randan Sargent struck up a sexual discussion with the "girl" online and asked her to send him naked photographs. His colleagues initiated the investigation after naked photos of the officer were found on a 14-year-old girl's computer.

A judge rejected Sargent's argument that he had been entrapped and refused to stay charges on July 28. He is now awaiting sentencing.

Check CTVBC.CA tomorrow for more on undercover online child sex investigations in B.C., and how undercover cops avoid being accused of entrapment.