Ottawa – An alleged Islamic State sympathiser shot dead by Canadian federal police had been detained last year for pro-ISIS social media posts, and an investigation has revealed extensive ties to foreign jihadists.Aaron Driver, 24, was killed on Wednesday during a police raid outside the home where he was staying with his sister in the town of Strathroy, Ontario, after he detonated a small explosive in the back seat of a cab.Royal Canadian Mounted Police (RCMP) Assistant Commissioner Mike Cabana and Assistant Commander for Ontario, Jennifer Strach with a video still of Aaron Driver in the background. (Lars Hagberg/AFP)Police said they acted to thwart an imminent "potential terrorist threat".Driver first came to the attention of authorities in October 2014 with tweets in support of ISIS and justifying the killing of a soldier standing guard at the Canadian National War Memorial in Ottawa by a young Muslim convert.In June 2015, a court ordered him to undergo religious counselling, wear an electronic monitoring bracelet and stay off the Internet. Those restrictions were gradually loosened and were scheduled to expire this month.A convert to Islam, Driver's views had apparently become increasingly radical after he began following the war in Syria online."If a country goes to war with another country or another people or another community, I think that they have to be prepared for things like [the October 22, 2014 attack in Ottawa]", Driver told public broadcaster CBC.'Mischief makers'"And when it does happen they shouldn't, they shouldn't act surprised. They had it coming to them; they deserved it."Still, he publicly disavowed violence. "I don't think there's a reason for Canadians to think that I'm a threat," he said.The Royal Canadian Mounted Police, however, revealed that Driver had been in "fairly constant contact" with violent extremists around the world.They included two members of the Islamic State group, a British youth arrested for his involvement in a terror plot targeting Australia, and Elton Simpson, one of two Americans who launched an attack on a Texas exhibition of caricatures of the Prophet Muhammad last year.Investigators searching Driver's home in 2015 found a recipe for homemade bombs on his computer.In a video released by the RCMP on Thursday, Driver warned Canadians: "You have Muslim blood on your hands and for this we will have your blood."He called Canadians and their allies "mischief makers" who spread "oppression and corruption".Muslim convert"You will pay for everything that you have done against us," he said, dressed in black clothes and a balaclava.According to Canadian media, Driver converted to Islam in his teens after a difficult childhood and a split with his father.CBC said his mother died when he was seven years old. Driver and his father – a Canadian soldier – recounted last year in interviews with the CBC how their relationship had become strained.The father, whose name was withheld, said his son had become increasingly withdrawn."It was like he turned out the lights and put a 'Do Not Disturb' sign on the door," the father told CBC."When he was living at home, he was very secretive; a lone wolf. He didn't bring friends over, never talked about where he was going and what he was doing," Driver's father said.Driver lived away from home during most of his teenage years.At age 17 he turned to religion. Baptised Christian in his birth province of Saskatchewan, he started reading the Bible, he said, but added "I just decided it couldn't possibly be the word of God."After exploring other religions, he converted to Islam.