The charges stem from an incident in May, when an arrest in Burlington, Ont. of two women in a stolen car turned up counterfeit citizenship documents, SIN cards and other identification.
The names and information in the documents were of other, actual people — eight of them — but had pictures of the two suspects.
Halton Regional Police said the two women were in the process of opening bank accounts in the victims' names.
A common link between the eight victims, investigators determined, was that they had all financed their vehicles through GM Financial.
Police, with help from GM Financial, say they followed the trail to an employee at the company, through which thousands of Canadians have bought GM vehicles.
The 48-year-old Toronto man was fired. He was arrested earlier this week and now faces charges in connection with the case, police say. The two women, who are from Quebec, have also been charged.
Similar ages, good credit
Following an internal investigation, GM Financial told CBC News on Saturday the former employee had inappropriately accessed information on some 2,200 of its customers.
The affected customers will be notified this week and offered one year of credit monitoring and identity theft protection for free, according to a company spokeswoman.
"GM Financial is taking this matter very seriously," said spokeswoman Chrissy Heinke via email.
Police say they believe the two women, aged 39 and 55, were "runners" in an identity theft ring and that they sought out women who were of similar ages and who had good credit.
The women inserted photos of themselves into documents bearing the victims' information, and used those documents to open bank accounts or lines of credit.
Police say the runners would keep a portion of the profits and give the rest to the ring leader. Police haven't found that person yet.