David Milgaard has been out of jail for 25 years now — but spent nearly that much time in a Saskatchewan prison for a murder he didn't commit.

Sunday marks 25 years since Milgaard was released from prison, after a court ruled he should have a new trial in the 1969 murder of Saskatoon nursing aide Gail Miller.

Saskatchewan decided not to prosecute him again, although he was not formally exonerated until 1997 and he was still legally considered a convicted killer at the time of his release.

Speaking at a University of Saskatchewan panel on wrongful convictions in 2015, Milgaard said he still sometimes felt angry about his experience, especially when speaking with others who have been wrongfully convicted.

"But I hope that in my presentations and the way that I try to bring a picture to people that listen to me talk, that it's done [with] ... generosity, caring and concern," he said.

Milgaard, who is from Winnipeg, was 16 at the time of the murder and was passing through Saskatchewan when Miller's body was found.

He was convicted in 1970 and sentenced to life in prison. ​In 1971, the Saskatchewan Court of Appeal and the Supreme Court of Canada both refused to hear Milgaard's appeal.

Seventeen years later, his team of lawyers applied to have the case re-opened.

Although he maintained his innocence and fought the conviction for years, he spent more than two decades in prison before his release in April 1992.

"The criminal justice system failed David Milgaard," concluded the Alberta judge who headed an inquiry into Milgaard's wrongful conviction that began in 2005.

In his 2008 report, Justice Edward MacCallum also noted the "epic struggle" led by Milgaard's mother, Joyce, who also maintained her son's innocence and fought for his release.

Serial rapist Larry Fisher was later linked to Miller's murder through DNA evidence. Fisher was arrested in 1997, 28 years after the murder of Gail Miller, and convicted in 1999. He died behind bars at the age of 65 in 2015.

The same DNA evidence was also used to help free Milgaard.

The inquiry's report revealed that police in Saskatoon received a tip in 1980 potentially pointing to Fisher as a suspect, but it was never followed up.

Milgaard received $10 million in compensation from the province for his wrongful conviction in 1999.