Dr. Aubrey Levin, a Calgary psychiatrist who has worked extensively with justice officials on criminal cases, has been charged with sexual assault.
Police say a 36-year-old man, one of Levin's long-term patients, alleges he was sexually assaulted repeatedly by Levin over a period of time.
Levin, 71, has regularly testified in court cases as an expert in forensic psychiatry, a factor that could widen the investigation, police said.
"He is very well known in the justice community," said police spokesperson Kevin Brookwell.
"Through both the solicitor general's office and Alberta Health Services — who he was employed with — all his client base, they're looking at all those files that he may have been working on, past and present, to see if anything is impacted as a result of this particular charge."
Levin's arrest Tuesday came a day after he was suspended by the College of Physicians and Surgeons of Alberta.
"Our process is completely separate from a criminal case being pursued," said college spokeswoman Kelly Eby.
"We will continue with our investigation, and that could include a review of his files. It will include interviews with witnesses, interviews with the victim."
The process could take several months and might result in a disciplinary hearing.
Police are asking members of the public who may have additional information to come forward. Levin worked at the Peter Lougheed Centre and lectured at the University of Calgary.
Levin came to Canada in the 1990s from South Africa. He worked as a psychiatrist for the military during the apartheid era.
Levin was released on bail and is scheduled to appear in court on April 8.