On the evening of Jul. 17, 2010, the RCMP in Okotoks, Alta., received a report of a domestic assault, and about six hours after the initial call, with the emergency response team deployed around his house, 39-year-old Corey Lewis stepped out the door.

"He took up a kneeling stance and raised an object to his shoulder and pointed it at the loudspeaker. The object he was holding appeared to have a silver tip and was dark in colour," according to Cliff Purvis, the executive director of the Alberta Serious Incident Response Team.

Const. Jason Krivoshein had an M-16 assault rifle with a flashlight attached, which he shined on Lewis, 39. Lewis, in a shooting stance, quickly turned towards the light.

"I took my gun off safe and I fired," Krivoshein told an inquiry later. Three of his six shots hit Lewis, who died about an hour later.

The object he was carrying – it was duct-taped to his hands – was an umbrella.

Emergency personnel respond following the shooting of Karen Lander by RCMP officers in Yellowknife, on March 14, 2012. An inquest into the shooting is now underway. (CBC)

Was this the kind of incident, commonly known in police circles and TV dramas as, "suicide by cop"?

An inquest now underway in Yellowknife may provide an answer to that question in another case. Karen Lander, 42, was carrying a firearm on March 14, 2012 when she was shot by RCMP, who were responding to a report of a suicidal woman.

It is a phenomenon that has been around since at least the mid-1980s, criminologists and other experts say.

And it may even be growing, according to a 2009 study, which found that 36 per cent of officer-involved shootings in a large sample from the U.S. and Canada were suicide by cop.

Not easy to determine

Investigators interview neighbours on July 18, 2010, after the fatal police shooting of Corey Lewis outside his home in Okotoks, Alta. (Jennifer Lee/CBC)

In the Okotoks case, police had entered his home earlier in the evening and one officer said that he saw Lewis holding a rifle, so the police retreated. A check of the long-gun registry revealed Lewis owned five long-barrelled firearms.

Another officer told the inquiry that Lewis' wife Naydene, an Okotoks town councillor, had been concerned her husband had not been taking his anti-depressants.

The day after his death, Purvis told a media conference that they had discovered a note on the stairs inside the front door. Then he said, "ASIRT is investigating the possibility that the deceased intended suicide when he engaged the police."

Earlier that year, on Jan. 9, John Wilcox was stopped by an RCMP officer in North Vancouver after he had collided with a parked car and then the officer's police car.

Both men got out of their vehicles, and the officer told an inquest that he ordered Wilcox, 39, to get down on the ground.

He did but then got up, advanced towards the officer while reaching into his pocket. He pulled out a black object and the officer fired, striking Wilcox.

The scene Jan. 9, 2010, on the Dollarton Highway in North Vancouver where John Wilcox was shot by an RCMP officer after his vehicle collided with a police cruiser. (CBC)

The officer knew Wilcox from a previous domestic disturbance, when Wilcox threatened to shoot the police who had shown up at the scene, the officer told the inquest.

Wilcox, a talented animator, suffered from bipolar disorder. The object he took from his pocket was a cellphone.

After he was shot, Wilcox said, "Why don't you kill me? Just kill me now. Why don't you kill me?" witness Claire McGivern told CBC News.

Wilcox would later die in hospital.

Was this a suicide by cop? The inquest ruled it was homicide, with mental illness a significant condition contributing to death, and no charges were laid.

Simulated weapon possession

Determining motives and who is at fault in cases like these poses a challenge for investigators.

Particularly as, "in the early to mid-1980s, a phenomenon began to emerge in the United States" that people were using a law enforcement response to try and end their own lives, John Violanti and James Drylie write in their 2008 book, Copicide: Concepts, Cases, and Controversies of Suicide by Cop.

The phenomenon has been called suicide by cop since that time, and it has appeared in news headlines since at least 1987. It has also been the subject of a number of books and many professional journal articles.

Incidents seem to be more common. A 1998 study of police shooting cases in Los Angeles county from 1987 to 1997 found that 11 per cent of those cases can be classified as suicide by cop.

In that 2009 study, which was co-authored by Peter Collins of Toronto's Centre for Addiction and Mental Health, 36 per cent of officer-involved shootings were classified as suicide by cop.

The study sample included 707 cases from the U.S. and Canada between 1998-2006.

It also found that in 19 per cent of the cases, the person "simulated weapon possession to accomplish their suicidal intent."

Some other findings from the study, which the authors say is "the largest known sample" of officer-involved shootings:

• 95 per cent of the suicide-by-cop subjects were male;
• 62 per cent of the subjects "had a confirmed or probable mental health history;"
• 48 per cent of the confirmed mental health subjects suffered from depression or some form of mood disorder;
• 87 per cent of the cases had "suicidal communications by the subject at any point prior to or during the incident;"
• 14 per cent of the suicide-by-cop subjects left a suicide note;
• 61 per cent of the subjects talked about suicide during the incident and 79 per cent of those subjects referred specifically to suicide by cop.

Another American study published in 2000 observed that "suicide by cop situations are unpredictably dangerous and require at least the same level of caution as any other type of police intervention with potentially violent persons."

Rebecca Stincelli, a former law enforcement instructor in California and the author of a book titled Suicide by Cop, has interviewed survivors of such attempts and says on her website that these people indicated they wanted to be killed by police "because they could not pull the trigger themselves and they knew, when forced with the circumstances, the police officer would respond with deadly force."