JASPER, AL — A man was riding his lawn mower when it exploded, killing him and his dog and hurling pieces of the mower over the roof of his house.

James Larry McAnnally was killed instantly when the 11-horsepower mower exploded Monday. His age was not available.

Pieces of the mower were found on the roof, and strewn up to 100 feet away.

Investigators for the Federal Bureau of Alcohol, Tobacco and Firearms joined a probe of the death Tuesday.

McAnnally had not started cutting his grass but had driven a short distance across his back yard when the lawn mower exploded. His dog was in the back yard.

Jaime Reyes, chief agent in the ATF office at Birmingham, said the agency was called "because it is an undetermined type of explosion."

The coroner said pieces of the mower were found on the roof of McAnnally's home in north Jasper and the steering wheel was in the front yard. Other pieces were strewn up to 100 feet away in neighboring yards. He said the explosion was heard up to a mile away.

Fire Chief John Dutton said gasoline fumes could have caused the explosion, which he described as being unlike anything he had previously seen.