After receiving a morning tip from the United States about an imminent terror attack, Canadian authorities identified the suspect within hours and a tactical squad descended on a quiet residential street in Strathroy, Ont., intercepting the bomb-carrying man as he was about to leave town in a taxi Wednesday afternoon.
The suspect, 24-year-old Aaron Driver, died during the raid by the RCMP's Emergency Response Team, either from an officer's shot or by a device that he detonated from the back seat of the taxi outside his house.
"It was a race against time," RCMP Deputy Commissioner Mike Cabana told reporters on Thursday.
While officials praised the force's successful intervention, the episode also underlined the limits of the authorities' ability to control wannabe terrorists with judicial tools such as peace bonds.
Mr. Driver, a former Winnipeg resident long known for his sympathies toward the Islamic State, had been arrested in June of 2015. There was not enough evidence for criminal charges and he was released under a peace bond that required him to report regularly to an RCMP officer. But he was not under physical surveillance and an earlier bond condition that he wear an electronic tracking device had been rescinded in February.
"He was being supervised. The RCMP took the necessary steps to take him to court before a judge and put conditions on him," Deputy Commissioner Cabana said.
But he added that "He's one among several who have potential criminal intents. The ability to put them under surveillance 24 hours a day, seven days a week, does not exist."
Public Safety Minister Ralph Goodale acknowledged the limits of the peace bond. "No tool in dealing with these circumstances will be perfect. But from the investigation, we will learn any lessons that need to be learned," he said.
Some officials have felt that peace bonds, while imposing some restrictions on the activities of suspects, give little insight into what would-be terrorists do behind closed doors.
RCMP Assistant Commissioner Jennifer Strachan said there was no sign that Mr. Driver had an accomplice.
The man in the martyrdom video had pledged allegiance to IS leader Abu Bakr al-Baghdadi.
The Amaq news agency, which is close to IS, referred to Mr. Driver as a "soldier of the Islamic State," according to the SITE Intelligence Group, which tracks extremist online activities.
The RCMP had been alerted on Wednesday by the U.S. Federal Bureau of Investigation that a masked man had made a martyrdom video and was expected to strike in Canada within 72 hours.
The tip came in at about 8:30 a.m., and by 11 a.m., Canadian authorities determined that it was Mr. Driver.
Brenda Carreiro, owner of the company Leo's Taxi, in Strathroy, told The Globe and Mail that Mr. Driver had asked to be taken to Citi Plaza, a mall in downtown London, 40 minutes away.
Assistant Commissioner Strachan said investigators have not yet determined the target of the alleged plot. Citi Plaza is not the main mall in London, but it is located near the city's Via Rail train station and the Greyhound bus terminal.
Transit agencies in Toronto and Vancouver have confirmed that they were warned of a security threat just before Wednesday's police operation.
Assistant Commissioner Strachan said police had taken position around Mr. Driver's house at about 4:30 p.m. on Wednesday, but they had not expected that he would call a taxi.
Ms. Carreiro said that as Mr. Driver got into the back seat of the cab, he said that he wanted to go to Citi Plaza in London. "The driver said he started to reverse and heard a bunch of gunshots, and [someone yelled], 'Just get out of the car and lay on the ground,' " Ms. Carreiro said.
Assistant Commissioner Strachan said Mr. Driver detonated an explosive device that he had with him. Photographs released by the RCMP show that the back seat was shredded by the blast.
The taxi driver, who suffered minor injuries, told The Globe that he didn't remember the explosion, only the sound of gunshots. He declined to comment further.
Mr. Driver's father, Wayne, told the National Post that "our worst nightmare has come true. As sad and shocked as I am, it doesn't surprise me that it has come to this. Aaron was a good kid who went down a dark path and couldn't find the light again," he said.
Aaron Driver was known for making social-media posts supporting the Islamic State, using aliases such as Harun Abdurahman.
In addition, the RCMP said on Thursday, he had been in touch with several jihadis and terror suspects.
Deputy Commissioner Cabana said Mr. Driver was in "fairly constant" contact with a British youth later arrested for his role in a plot targeting Anzac Day celebrations in Australia.
In May, 2015, Mr. Driver exchanged encrypted messages with two IS jihadis from Britain, Reyaad Khan and Junaid Hussain, who were later killed in a drone strike in Syria.
He also was in touch through Twitter with Elton Simpson, one of the gunmen in an attack on a Garland, Tex., exhibit of cartoons of the Prophet Mohammed.
In the martyrdom video, which was shown by the RCMP, the masked man said Canada had received many warnings and could not escape retribution for fighting IS.
"There's a fire burning in the chest of every Muslim and that fire can be cooled only by the spilling of your blood," the man said in the video.
He added: "You will pay for everything you have brought on us."
Mr. Driver's neighbours in Strathroy said he worked at Meridian Lightweight Technologies Inc., a company that manufactures automotive parts using magnesium.
While he kept a low profile, his next-door neighbour recalled odd incidents in recent months.
"He was just sort of in and out all of the time," Maria Pereira said.
"We'd hear banging in the back shed. I thought someone was living there," she said, noting that it began in the winter, when Mr. Driver is said to have moved into the house.
Ms. Pereira said she called Strathroy-Caradoc Police Service on July 31 after she heard what sounded like loud firecrackers. The police drove by, she said, but she doesn't remember them going to speak with the resident.
(When asked to confirm whether such a call was received or acted upon, a spokesperson for Strathroy police said, "You'll have to file a freedom of information request for that.")
Ms. Pereira said she saw Mr. Driver's sister leave the house with her children on Monday.
The estranged son of a Canadian Forces corporal, Mr. Driver grew up in Ontario but was living in Winnipeg when his tweeting activities caught the attention of authorities in 2014.
He was arrested in June of last year because of concerns about his activities online. He agreed to a peace bond that restricted his movements and online activities.
The peace-bond conditions that he agreed to in February included living with his sister in Strathroy, as well as not possessing firearms or explosives, not possessing cellphones or computers, staying off social media and not possessing anything bearing the symbols of the Islamic State.
The ban on computers and cellphones was to end on Aug. 31.
In a 2015 interview with the CBC, Mr. Driver said he was not a terrorism threat, but he added, "I'm okay with soldiers or police officers being targeted" because of what they did to Muslims.
"Seeing some of the things that are happening in Syria, it infuriates you and it breaks your heart at the same time, and I think that if you know what's going on, you have to do something," he said.
With reports from Michelle Zilio in Ottawa, Michael Pereira in Winnipeg and The Canadian Press