Canada's police chief has resigned after admitting he misled parliament in the case of a man deported to Syria over suspected terror links.
Mr Arar says he was tortured in Syria
Maher Arar claims he was tortured in Damascus after being detained by US officials while changing planes in the US on a journey from Tunisia to Ottawa.
A Canadian government inquiry cleared him of any involvement in terrorism.
Royal Canadian Mounted Police (RCMP) Commissioner Giuliano Zaccardelli said his force had made major mistakes.
In a letter to Prime Minister Stephen Harper, Mr Zaccardelli said the controversy surrounding the case was making it increasingly difficult for him and his officers.
"Commissioner Zaccardelli submitted his resignation to me and I have accepted it. [He] has indicated to me that it would be in the best interests of the RCMP to have new leadership," Mr Harper said.
Mr Arar was detained and questioned by US customs agents in New York's JFK airport in September 2002 while changing planes on his way back from a holiday in Tunisia.
He was subsequently deported to Syria. A Canadian government inquiry supported his claims to have been tortured during almost a year of imprisonment in the country.
The inquiry also took Canada's police force to task over the incident, criticising the force for spreading misleading and false information about Mr Arar.
Canada made a formal protest to the US over the case in October.
Mr Harper said that he had received assurances from US President George W Bush that the matter would be looked into seriously.