Just days before Christmas, a Calgary woman's apartment was surrounded by tactical units with guns drawn. Responding to a realistic-sounding 911 call, Calgary police believed a man had been shot and two others were being held hostage in the home.

A week later, an unarmed Kansas man was shot dead on his porch after a bogus emergency call about a hostage-taking prompted police to surround his house in Wichita.

Not only were both incidents cases of "swatting" – a hoax designed to get a police SWAT team to respond to fake emergency calls about a gunman or a bomb – they were allegedly perpetrated by the same California man.

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Calgary police said Tuesday they have charged Tyler Raj Barriss, 25, of Los Angeles, with mischief and fraud charges following the incident on Dec. 22 that saw officers along with police dogs surround the unnamed woman's apartment. Police revealed few other details but said investigators identified a suspect who had made contact online with the woman earlier that day and that she was targeted because of her "online persona."

Mr. Barriss is being held without bail in Los Angeles in connection with the hoax emergency call that resulted in the fatal police shooting in Kansas on Dec. 28. Police say Andrew Finch, 28, moved his hands toward his waist when he was killed.

Mr. Barriss has an alleged history of making bogus calls to authorities.

In the Calgary case, no one was hurt. But police warn the increase they are seeing in swatting calls puts everyone in danger.

"It's very frustrating because we have to take these calls seriously, we have to take them at face value," said Calgary Police Service Acting Deputy Inspector Peter Siegenthaler. "It puts not just officers, but the public at risk."

On the evening of Dec. 22, Calgary 911 received a call from a man who claimed he had shot his father and was holding his mother and younger brother hostage, and giving an address in Calgary's Bankview neighbourhood. Officers from patrol and the tactical unit were dispatched to the low-rise apartment building and began evacuating other units.

At about the same time, the woman had been warned by an "online colleague or friend" about the swatting hoax, Deputy Insp. Siegenthaler said. She called 911 herself and, as she exited her apartment, police confirmed there was no shooting or hostage situation.

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"Anyone can make these calls. You don't have to be very sophisticated," Deputy Insp. Siegenthaler said. "We know that swatters can be teenagers in their bedroom making a swatting call while Mom and Dad watch TV."

The hoax call that resulted in the fatal police shooting in Kansas reportedly was made after a dispute over a small wager online in a Call of Duty online video game tournament, according to Dexerto, a news service focused on gaming. However, the mother of the victim has said Mr. Finch was not a video game player.

Last week, Mr. Barriss told a Los Angeles Superior Court judge he would not fight efforts to send him to Wichita to face charges.

He has been charged in Kansas with making a false alarm, according to court documents. The charge for calling police or a fire department and knowingly giving false information is a low-level felony in Kansas that carries a maximum of 34 months in prison.

He is next scheduled to appear in court on Jan. 17.

Mr. Barriss was released from the Los Angeles county jail last year after serving less than half of a two-year, eight-month sentence for phoning in two fake bomb threats in 2015 that cleared out ABC Studios in Glendale, Calif., just north of Los Angeles.

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Glendale police said at the time that Mr. Barriss lived with his grandmother and was unemployed. There was no evidence to indicate that he would have actually carried out those threats.

Investigators later connected him to about 20 other alleged incidents involving bogus phoned-in threats to universities and media outlets, said Glendale Police spokesman Sergeant Dan Suttles.

With files from Andrea Woo and The Associated Press