Here are some of the deadliest mass killings in recent Canadian history:
April 19, 2020: Seventeen people are killed after a man who at one point wore a police uniform and drove a mock-up cruiser travelled across northern Nova Scotia. An RCMP officer is among the dead. Police say the suspected shooter, 51-year-old Gabriel Wortman, was killed after being intercepted by officers in Enfield, N.S.
Aug. 10, 2018: A gunman opens fire in Fredericton, N.B., killing two municipal police officers and two civilians: Const. Sara Burns, Const. Robb Costello, Donnie Robichaud and Bobbie Lee Wright. Matthew Raymond is arrested and charged with four counts of first-degree murder.
April 23, 2018: Alek Minassian drives a white van along a crowded Toronto sidewalk, killing 10 people and seriously injuring 16 others. Minassian later admits in court to carrying out the attack in retribution for years of sexual rejection and ridicule by women. He's awaiting trial on 10 counts of first-degree murder and 16 of attempted murder. The judge has said the case will turn on Minassian's state of mind at the time of the attack, not whether he did it.
Jan. 29, 2017: Six people are killed and eight injured when a man goes on a shooting rampage at a Quebec City mosque. University student Alexandre Bissonnette, who had taken far-right political positions on social media, pleads guilty.
Dec. 29, 2014: In the worst mass shooting in Edmonton, a man suspected of domestic violence shoots and kills six adults and two young children in two different homes. Phu Lam then killed himself in a restaurant where he worked.
June 4, 2014: A man uses a semi-automatic rifle to fatally shoot three RCMP officers and wound two others in Moncton, N.B. The rampage by Justin Bourque was the deadliest attack on the RCMP since four officers were killed by a gunman in Alberta in 2005.
April 15, 2014: Matthew de Grood kills five people at a house party in northwest Calgary. A judge in 2016 found de Grood not criminally responsible for the killings because he was suffering from schizophrenia at the time.
March 3, 2005: James Roszko shoots and kills four RCMP officers near Mayerthorpe, Alta., before turning the gun on himself. Constables Anthony Gordon, Peter Schiemann, Leo Johnston and Brock Myrol were ambushed by Roszko, 46, at Roszko's farm northwest of Edmonton.
April 5, 1996: Angered by his wife's divorce action, Mark Chahal kills her and eight other members of her family in Vernon, B.C., before shooting himself.
Sept. 18, 1992: A bomb kills nine strike-breaking workers at the Giant Yellowknife gold mine in the Northwest Territories.
Dec. 6, 1989: A man with a semi-automatic rifle storms into an engineering classroom at the Ecole Polytechnique in Montreal, asks men to leave and then kills 14 women before turning the gun on himself. Gunman Marc Lepine says he was "fighting against feminists" he blamed for his troubles.
Sept. 1, 1972: An arson attack on a downtown Montreal night club kills 37 people and injures 64. Gasoline was spread on the stairway of the Blue Bird Cafe and then ignited. Most of the deaths occurred in the Wagon Wheel country-western bar upstairs. Three young men from Montreal who had earlier been denied entry for drunkenness were convicted and sentenced to life in prison.
The Canadian Press
Note to readers: This is a corrected story. A previous version said the officers killed in Fredericton in 2018 were with the RCMP. They were with the Fredericton Police.