The only Canadian on death row in the United States broke down and cried at his clemency hearing in Montana on Wednesday.
Ronald Smith's sister Rita Duncan was reading a letter he wrote to their mother after her death last year.
Mr. Smith covered his eyes, brushed away his tears and was patted on the shoulder by his lawyer.
Ms. Duncan said Mr. Smith has always loved her and she is proud to be his sister.
Mr. Smith's daughter, Carmen Blackburn, also cried as she talked about her father and his remorse. She said she wishes she could take away the pain she can see behind his eyes.
Mr. Smith is asking the Board of Pardons and Parole to recommend his death sentence for killing two men in Montana 30 years ago be commuted.
A psychologist told the hearing that Mr. Smith is a model prisoner and poses little threat to the people around him. Dr. Bowman Smelko said Mr. Smith has shown improvement during his time in prison, and his cognitive ability has jumped 16 points from low to high average.
"He was not exposed to drugs and alcohol. He was not exposed to chaos. He has demonstrated significant change in attitude, thoughts and behaviour," Mr. Smelko said. "He is what would be considered a model prisoner in the modern setting."
Mr. Smelko added that Mr. Smith has shown remorse about what he did.
The hearing has also heard that Mr. Smith is well-liked by prison guards. Two are expected to testify on his behalf.
The hearing, which represents Mr. Smith's final fight for life, began with a last-minute addition to the witness list.
The hearing heard that a Canadian consular official based in Denver plans to read a statement from the government asking the board to spare Mr. Smith's life. Ottawa had already written a letter favouring clemency, but critics say the government's support has been tepid.
Mr. Smith lawyer Greg Jackson told the hearing in his opening arguments that the bid for clemency isn't meant to minimize the "terrible crime" that Mr. Smith is guilty of, but "is a request for mercy."
Mr. Jackson said Mr. Smith is not the same man who killed the young men near East Glacier, Mont., in 1982.
"He is a changed man" said Mr. Jackson. "He has reformed his life. He has expressed deep remorse and deep regret.
"He has a life that is worth preserving."
Mr. Smith was brought into court in chains and wearing a bright orange prison jumpsuit. He sat at a table directly in front of the witness box.
The chairman of the three-member panel told the packed courtroom that he would have "zero tolerance" for any kind of outbursts.
The board is to give its final recommendation the week of May 21.
Mr. Smith, 54, has been on death row since 1982 after he shot and killed Thomas Running Rabbit and Harvey Mad Man Jr. while he was high on drugs and alcohol.
After decades of appeals, he has one last chance to make a case before the board as to why he should not be executed. Once the parole board delivers its recommendation, Mr. Smith's fate will ultimately end up in the hands of Montana Gov. Brian Schweitzer, a Democrat whose term in office runs out in November.
"It's got to be over. Thankfully we've hit this point in time where there's no more long drawn-out waiting. We're going to get it finished one way or the other," Mr. Smith said in March in an interview with The Canadian Press.
"It's time. It would be nice to keep it going for my family's sake, but once the decision is made — and if it goes against me — it's over. There's nothing else to it."
Mr. Smith, originally from Red Deer, Alta., was 24 and had been taking LSD and drinking when he and Rodney Munro marched the two men into the woods where Mr. Munro stabbed one of them and Smith shot them both in the head.
It was a cold-blooded crime. They wanted to steal the men's car, but Mr. Smith also said at the time he wanted to know what it was like to kill someone.
"I'd like to be able to take it back. I can't but I wish I could," he said in March.
Mr. Smith pleaded guilty to two charges of deliberate homicide and two charges of aggravated kidnapping in February 1983 and requested the death penalty. He rejected a plea deal offered by prosecutors which would have given him life in prison.
He later changed his mind and asked the District Court to reconsider the death penalty. That has led to three decades of legal wrangling.
The hearing is being held at the courthouse in Deer Lodge, about 10 kilometres from Montana State Prison, where Smith has spent the last 30 years.
Almost 40 witnesses, including Mr. Smith himself, are expected to testify. Many relatives of Running Rabbit and Mad Man Jr. have made the journey.