TORONTO -- A senior citizen who spent more than half his life branded as his wife's killer finally cleared his name on Monday amid new evidence that she died of natural causes.

The Ontario Court of Appeal formally acquitted John Salmon of manslaughter in the 1970 death of Maxine Ditchfield, reversing a verdict that once sent him to prison for nearly four years.

"I'm ecstatic," Salmon said outside court. "I'm happy, I'm pleased I finally got this closure."

The former welder, now 75, was originally convicted after a jury decided he beat Ditchfield to death in a drunken rage. But Monday's court decision was based on evidence, unearthed by the Association in Defence of the Wrongly Convicted, that she died of injuries from several falls after having a stroke.

Salmon's son Randy said he hoped the acquittal would start to mend the damage done to his father, and prompt a different response from people who have shunned him for decades.

"Hopefully, now that this is done, people will show a little compassion towards him that he was wronged," Randy Salmon told The Canadian Press. "He had to live with that for 45 years. He's free and should be free."

Salmon's ordeal began in September 1970 after Ditchfield fell out of her chair during a night of heavy drinking with friends in Woodstock, Ont.

Salmon told his trial that his common-law wife became increasingly clumsy and fell several more times in the hours after her initial tumble. He eventually called a doctor after she became unresponsive. Ditchfield died in hospital the next day.

An autopsy determined she had sustained several head injuries delivered with "extreme force." Pathologist Dr. Michael Dietrich told Salmon's trial that her injuries were from a severe beating.

Salmon, who argued unsuccessfully he had not harmed her, maintained his innocence long after he was granted parole in 1974. He enlisted help from the advocacy group in 2000 after learning of Steven Truscott's decades-long battle to clear his name of a wrongful murder conviction.

Three pathologists the group hired to re-examine the medical evidence concluded Ditchfield's injuries weren't consistent with a beating. They found her falls had damaged one of her arteries, caused a blood clot to form, and triggered a fatal stroke.

In court Monday, prosecutors apologized to Salmon for what they called a miscarriage of justice.

Lawyer James Lockyer said it was a pleasure to have helped Salmon clear his name

"It's a great relief that it's over finally for him," Lockyer said. "Forty-five years is a long time to wait."

Randy Salmon said the saga has done lasting damage that can't be redressed by the court decision. His childhood was marred by seeing the father he idolized turn into an unhappy, emotionally remote man after his prison sentence, he said.

"When you're growing up and your dad has that burden on his shoulders, he's not as close to you as he should be," he said. "We've endured that hardship where our dad wasn't real loving towards us."

The impact was even felt into his adulthood: Randy Salmon said he was let go from the job he had held for 30 years mere months after his father's case reappeared in headlines.

But if Monday's decision can't address the past, he said, he hoped it would bring greater peace to his father's twilight years.

"It's going to lift that burden. He's a free man."