1 of 3
Ohio Department of Rehabilitation and Correction, Associated Press
FILE - This is an undated photo provided by the Ohio Dept. of Rehabilitation and Corrections shows Michael Webb, scheduled to be executed next month for the arson death of his 3-year-old son two decades ago. Webb doesn’t dispute the blaze was arson, but denies starting the fire and says investigators using now-discredited methods came to the wrong conclusion about where in the house it may have broken out. It was a mistake that he says points to someone else as the culprit.

COLUMBUS, Ohio — An Ohio death row inmate says updated arson science could help exonerate him in the blaze that killed his 3-year-old son.

Ohio's Parole Board is scheduled to take up a plea for mercy Wednesday from Michael Webb.

Webb says a new analysis of the 1990 fire shows it could have started just about anywhere on the main floor of his house. And that points to another culprit, he says.

Prosecutors say his argument is nothing new and not backed by the evidence.

Webb's case is part of new legal frontier around the country: Defense attorneys are using the latest research on fire to challenge arson convictions, in much the same way they have used DNA to exonerate people convicted of murder.