David Milgaard was actively helping people who claim they have been wrongfully convicted right up until his sudden death, including two Indigenous sisters who have been incarcerated for nearly 30 years.

The victim of one of Canada's most notorious miscarriages of justice, he spent 23 years in prison for a 1969 rape and murder he didn't commit.

Milgaard died over the weekend after a short illness at the age of 69.

Odelia Quewezance, who was convicted of second-degree murder in a 1993 killing she denies taking part in, told The Canadian Press Milgaard was her “biggest supporter,” and that he was “like a brother, an angel” to her.

“I'm really heartbroken about him, but I honestly believe today that he's still watching over us,” she said in a phone interview.

She was speaking from Keeseekoose First Nation in Saskatchewan after being approved for a brief visit home, her first in years, she said.

Her husband first reached out to Milgaard around two years ago about her case, Quewezance said, and they had communicated often ever since.

Milgaard wished her well just a few days before her visit home, she said.

James Lockyer, a Toronto-based lawyer who helped with Milgaard's exoneration in 1997 and helped found the advocacy organization Innocence Canada, was in Keeseekoose to meet with Quewezance on Monday.

Lockyer said he wouldn't be working on the case if it weren't for Milgaard championing Quewezance, who was 20 at the time she was arrested in the killing of 70-year-old farmer Anthony Joseph Dolff, near Kamsack, Sask.

Her sister Nerissa, who was 18 then, was also convicted and sentenced to life in prison with the possibility of parole after 10 years.

Nerissa is in prison at an institution in British Columbia's Fraser Valley, where Lockyer said he met her for the first time in person on Sunday.

Odelia said she spoke with Nerissa for the first time in a while on Monday.

It's been about 19 years since the sisters last saw each other in person.

Lockyer said they were present when Dolff was fatally stabbed, but they were not involved in the killing. Someone who was a youth at the time confessed to the killing at trial, testifying that the sisters were not involved, he said.

Milgaard had urged Lockyer to look at the sisters' case. He decided to take it on after speaking with them and reading transcripts from the trial, he said.

The evidence that the sisters were involved in the killing was dependent on the police officers who arrested them, Lockyer said, explaining that the RCMP claimed they gave a series of statements that weren't recorded and became “more and more incriminating” over the course of five days.

A provincial judge had ordered them sent to a nearby jail 24 hours after their arrest, he said, but the pair were held by the Mounties for four more days.

Lockyer described them as “two young Indigenous women, essentially at the mercy of a whole bunch of RCMP officers for five days with no protection.”

“It's apparent to me that the statements that they gave that were the later statements, that were incriminating, are entirely unreliable,” he said.

The sisters are part of the staggering statistic that Indigenous women make up nearly half of women incarcerated at federal prisons when they comprise less than five per cent of Canada's population, Lockyer said.

“Forget for a moment the miscarriage of justice at their trial, they're still (incarcerated), 20 years after they were eligible for parole,” Lockyer said.

“They need to be able to live the rest of their lives as free persons.”

The only remaining route forward to have the Quewezance sisters' convictions quashed is through ministerial review, said Lockyer, who filed an application with Justice Minister David Lametti on their behalf in December.

The minister has appointed a counsel in Ottawa to review the case on his behalf, Lockyer said.

“We then have to convince her, and the minister himself, that this case is a miscarriage of justice,” he said.

In a statement mourning Milgaard's death, the Congress of Aboriginal Peoples said “the faith and strength he showed at the worst of times is an inspiring story that continues to drive advocates for those unfairly targeted.”

National Vice-Chief Kim Beaudin said Milgaard's support for Indigenous people “struggling within the Canadian justice system will not be forgotten.”

“His work to help the Quewezance sisters has helped bring them closer to finding justice.”

Milgaard was just 16 when he was charged and went on to be wrongfully convicted in the rape and murder of a woman in Saskatoon in 1969.

The Winnipeg-born teenager had been passing through the city on a road trip with two friends at the time nursing aide Gail Miller was raped and killed.

Milgaard had described prison as “a nightmare.”

He was released in 1992 after his mother, who fought relentlessly to clear his name, pushed to get the case heard by the Supreme Court of Canada. His conviction was thrown out and he was later exonerated by DNA testing in 1997.

A man named Larry Fisher was convicted in 1999 of first-degree murder in Miller's death and sentenced to life in prison, where he died in 2015.

The Saskatchewan government issued Milgaard a formal apology and awarded him a $10-million compensation package.