Canadian police officers were not justified in using a Taser gun on a Polish immigrant at Vancouver airport, an inquiry has found.
Robert Dziekanski, who did not speak English, died after being stunned five times with a Taser in 2007.
British Columbia's attorney general said a special prosecutor would examine the possibility of criminal charges against the four officers involved.
The case sparked outrage across Canada.
Mr Dziekanski, 40, was a first-time traveller who had been emigrating to Canada, where his mother lived.
He disappeared for several hours at Vancouver airport, and grew distressed when he was told by an official that his mother was not there.
Airport workers called police after he threw a computer and a chair.
Thomas Braidwood, the head of the inquiry commission, said police had not been justified in using the Taser, and that Mr Dziekanski had not posed a threat to the officers, as had been claimed.
He said that the five jolts and the ensuing struggle with police had "contributed substantially to Mr Dziekanski's death".
The inquiry was set up after a video, filmed by a bystander, was released to the media.
Mr Braidwood said the video "shocked and repulsed people around the world".
According to the video, before his death, Mr Dziekanski asked the policemen in Polish: "Have you lost your minds?"
The commissioner of the Royal Canadian Mounted Police, William Elliott, apologised to Mr Dziekanski's mother, Zofia Cisowski.
"I would like to express sincere regrets and apologise unconditionally for the role of the RCMP in this tragic death.
"Our policies and training were inadequate. The actions of our officers were inappropriate," he said at a news conference.
One of the officers involved is already suspended due to an investigation into a separate incident, while the other three remain in their positions but are not involved in "front-line policing", he said.