Kenny Richey says he is giving up hope

The prosecution alleged that he started the fire as revenge after his former girlfriend Candy Barchette had gone off with another man.

But Richey has always protested his innocence - and alleged that he had actually tried to get into the building to save Cynthia.

BBC Scotland's Frontline programme has uncovered evidence which reveals the fatal fire was probably started by accident.

Fire investigator Dick Custer said that a photograph of the living room carpet showed an irregular burn pattern which was frequently interpreted as being evidence of a flammable liquid having been used as an accelerant.

"This type of pattern is entirely consistent with a furniture fire as well," he said.

What angers me is that we are so arrogant in our own rights that we won't just look at the system and say maybe there is something wrong

Shirley Smith, State representative

"In my best analysis of the fire situation on the evidence that I've seen so far, I would say it's most likely to be a match or cigarette.

"Finally, the patterns that are evident at the end of the fire are just as easily caused by a furniture fire as they are by an arson fire."

Neighbour Peggy Villearreal, who gave evidence at Richey's trial, had alleged that Cynthia Collins had a fascination with matches.

"Cynthia was always playing with matches, or trying to," she said.

The local fire brigade had been called out on three occasions to deal with fires started by Cynthia - evidence which was never heard in court.

Several prosecution witness have also changed their stories.

Cynthia Collins was alleged to have liked matches

But Richey has almost exhausted the American appeals system and his best chance now is a plea for clemency.

Shirley Smith said she was angered that the justice system would not go back and look again at such cases.

"What angers me is that we are so arrogant in our own rights that we won't just look at the system and say maybe there is something wrong, maybe Kenny Richey is innocent," she said.

The Democrat politician - who is calling for a moratorium on all death penalty cases in Ohio - could be one of Richey's few remaining hopes.

However, the Scot admits that the waiting is getting to him.

"There's always a part of me that dies, always a part of me that gives up hope, and a major part of me that says no, bring it on, you know, just kill me now, put an end to it.

"It's been dragging on 14 years, that's too long," he said.