On Wednesday evening, residents in the Strathoy neighborhood of Ontario, Canada were startled to hear the words, “Put down your weapon!” then gunfire. What they were hearing was a confrontation between police and a would-be suicide bomber as they shot him dead. The suspect, 23-year-old Aaron Driver of Winnipeg, Manitoba, had allegedly been in the final stages of a plan to carry out a suicide attack in a crowded area during rush hour, but was thwarted after police received intelligence of the plot and Driver’s whereabouts. News reports noted that the tip came from the U.S. FBI.

Driver had been previously known to the Canadian Security Intelligence Service (CSIS). In October of 2014, he Tweeted not only his support of ISIS (under the name Harun Abdurahman), but also praised the attack on Parliament Hill that same month by Michael Zehaf-Bibeau, who killed one soldier and rushed into the hall firing before he was shot dead himself. Driver described the attack as “justified.” After he was arrested for the Tweets, Driver entered into what is known as a “peace bond,” in which, according to a story from CBC/Radio Canada, he agreed to the government’s conclusion of “consenting or acknowledging that there are reasonable grounds to fear that he may participate, contribute—directly or indirectly—in the activity of a terrorist group.”

Despite the events of Wednesday night, Driver’s former lawyer said that there was no evidence or indication that Driver was affiliated with or directly connected to any terror group, much less ISIS. Under the terms of his peace bond, besides the obvious—no associating with any terror organization—and being banned from using a cell phone or computer (both of these stipulations were set to expire at the end of August), he was also required to live at a specified address and to inform the Royal Canadian Mounted Police of any changes in status or address. It is not clear if the home where Driver was confronted and killed was the specified address he was required to live at, but neighbors said that the house was occupied by a man, a woman, three teenagers, and a young boy, who had apparently been living at the residence for about a year.

It is probable that Driver was under surveillance by CSIS or other authorities, but it was the tip from the FBI that set last night’s events in motion. The tip did not specifically name Driver as the suspected attacker, but it did warn that someone was plotting a mass casualty attack in the area during rush hour. As soon as the information was passed, Canadian national and local law enforcement agencies moved to disseminate the warning. Minister of Public Safety and Public Preparedness Ralph Goodale alerted Prime Minister Justin Trudeau, but it was agreed that, based on the information at the time, the national alert level would remain at “medium.” Locally, however, residents around the area of the home where Driver was confronted were evacuated early on, and all others in the neighborhood were told to stay inside.

According to early police reports, Driver was shot dead by SWAT team members after he detonated a device that injured himself and one other person (unidentified). He was in possession of another device that he might have intended to detonate as well. He was pronounced dead at the scene. This incident, coupled with recent so-called “lone wolf” and other coordinated attacks in Belgium, France, and Germany, have heightened fears of sleeper cells conducting directed attacks or individuals who otherwise have no links to terror organizations carrying out attacks “in the name of.” Obviously these two elements are extremely difficult to detect and track, and any attack is an easy setup for groups like ISIS to take credit for, which adds to the appearance of their worldwide reach. Last night’s operation was a victory, but intelligence services and law enforcement personnel have been hard-pressed to keep up with this dangerous game of Whack-a-mole.