CALGARY - Alberta's Justice Department plans to send letters to everyone who has ever undergone a court-ordered exam by a prominent Calgary psychiatrist who is facing sexual assault allegations from more than 20 of his former patients.

The letters notify former patients, some of whom are still in jail, that Dr. Aubrey Levin has been charged with sex crimes and ask anyone else with concerns to come forward.

Levin, 72, was frequently used by the courts to assess people and provide expert opinions at hearings. He was arrested last March and has since been charged with assaulting 21 male patients, most of whom, police say, where ordered to see him by a judge.

Alberta Justice is reviewing all criminal cases in which Levin offered testimony to ensure there were no miscarriages of justice. As part of that process, spokesman Josh Stewart says the Crown has reached out to everyone who was ordered to be under Levin's care.

"The letter just pretty much notifies them that Levin has been charged, there's a review under way and if they have any concerns or want to bring anything forward they can contact a lawyer, the Calgary Police Service, the College of Physicians and Surgeons or Alberta Justice," Stewart says.

"The review is ongoing. It's less than 100 (cases) so far, but the investigators didn't want to put a number on how many it could be because it is still going on."

Levin, who has had his medical licence temporarily suspended by the Alberta College of Physicians and Surgeons, is facing a month-long preliminary inquiry in June to see if there is enough evidence to proceed to trial. Levin is free on bail on condition that he remain in Canada, has no contact with the alleged victims and does not practise medicine.

Levin's lawyer, Alain Hepner, said he wasn't surprised that Alberta Justice was going to go through the numerous cases and check with other clients of the psychiatrist.

"I sort of sensed that was going to happen. I know one of the fellows who's (investigating) the ordeal. I knew him as a trial counsel and he's an honourable guy," said Hepner.

"I think he's just got a role to play and he's just doing due diligence."

Hepner said Levin was "well-respected" as a forensic psychiatrist and had a busy schedule in the courts. He said there are plenty of former clients who are fans of Levin.

"I'm getting calls from people who are very supportive of Levin and have given me their names and numbers and said if you need me, please call me."

Calgary defence lawyer Adriano Iovinelli, who had a client receive a letter, said he's never seen this kind of effort made to contact potential complainants. Traditionally, the Calgary Police would make a public statement, show a photograph about an individual and ask anyone with concerns to contact them, Iovinelli said.

"The door has been wide open by the Crown's office and they've gone the extra step of actually contacting these individuals and that's the first time I've ever seen that happen," Iovinelli said.

"You may actually have individuals that are serving penitentiary terms -- long penitentiary terms -- that may not even know what happened with Dr. Levin. So this is the further step of getting these letters out."

Levin is no stranger to controversy over his work as a psychiatrist. He faced heated accusations about his time as a military psychiatrist during apartheid in South Africa, where he earned his degree in 1963.

He was a psychiatrist at a military hospital in the 1970s where aversion therapy through electric shocks was allegedly used in an attempt to change the sexuality of gay soldiers. Levin is mentioned in a report entitled the "Aversion Project" that attempted to shed light on abuses of gays and lesbians in the military by health workers.

Media coverage of the South African Truth and Reconciliation Commission said that Levin was named by a Health and Human Rights Project submission as being a key figure in the abuse of gay men in the military. It acknowledges that the submission was based on anecdotal reports.

Levin has denied that he abused any patients under his care, and argued the submission was based on a distortion of the facts, according to an article in the South African Medical Journal.

A 2003 report compiled by the Gay and Lesbian Archive and the South African History Archive attempted to put together a history of Levin's work as a psychiatrist and any role he may have played related to gay and lesbian soldiers.

According to the report, Levin confirmed in a letter to the Truth and Reconciliation Committee that he had practised aversion therapy, but said that it was an accepted form of therapy at the time for patients who did not accept their homosexuality.

The report says two complaints were filed against Levin to what was then the South African Medical and Dental Council. Both complaints were dismissed. And Levin has denied in media reports that he ever administered shock therapy, saying the aversion therapy consisted of applying very slight discomfort to the arm of consenting patients.

After coming to Canada, Levin served briefly as regional director of the federal Psychiatric Centre Saskatoon as an employee of Correctional Service Canada and has been a licensed psychiatrist in Alberta since 1998.