Prime Minister Justin Trudeau intends to posthumously pardon Everett George Klippert who, because he admitted to police in the 1960s that he was gay, was deemed a dangerous sexual offender and sent to prison.

"The prime minister intends to recommend that a pardon under the authority of the Royal Prerogative of Mercy be granted posthumously to Mr. Klippert," Trudeau's office said in a media release.

The move was cheered Sunday by gay-rights advocates.

"It's fantastic that he'll get a posthumous pardon," lawyer Doug Elliott told CBC News.

As well, the statement said the Liberal government will also look to see whether pardons are "warranted" after reviewing the cases of other individuals who in the past were convicted on charges such as gross indecency and buggery.

"As Canadians, we know that protecting and promoting fundamental human rights must be an imperative for governments and individuals alike, and this includes gender identity, gender expression and sexual orientation," the weekend statement said.

Trudeau's office credited Klippert's case for being "instrumental" in Canada's decision to decriminalize homosexual acts between consenting adults.

Indefinite prison sentence

Klippert was questioned by the RCMP in 1965 during an arson investigation in Pine Point, N.W.T. He wasn't involved in the fire, but voluntarily said he'd had sexual relations with four men. He was charged with four counts of gross indecency, all for consensual, private, non-violent acts.

In 1966, Klippert was visited in prison by a Crown-appointed psychiatrist who concluded that Klippert's homosexuality was "incurable," and that he therefore met the criteria regarding dangerous sexual offenders.

A judge agreed and sentenced Klippert to preventive detention, meaning an indefinite term in prison.

The sentence was backed up by the Supreme Court of Canada in 1967, although Chief Justice John Cartwright suggested the laws regarding homosexuality be clarified, and that incarceration of harmless homosexuals was not their intention.

The Klippert case stoked considerable media and political interest. Just six weeks later, Pierre Trudeau, the Liberal government's justice minister (who would later become prime minister) introduced a bill that, among other things, called for the decriminalization of private, consensual homosexual acts between people over the age of 21.

"It's great that the young Trudeau is finishing the work that his father started," Elliott said.

Before homosexuality was decriminalized in 1969, people were routinely charged with gross indecency — a charge almost always applied to homosexuals — but rarely for private, consensual acts.

Klippert was released from prison on July 21, 1971. He was 69 when he died in in 1996.

"I never understood: Why didn't Pierre Trudeau let him out in 1969 when they decriminalized gay sex?" Elliott said. "They kept the poor guy who was responsible for shining a light on this issue in jail for another couple of years."

Last week, the prime minister confirmed he will march in Toronto's Pride parade on July 3, a move that would make history with Trudeau being the first sitting PM in Canada to take part in the event.