Former North Dakota congressional candidate Matt Mechtel, who was under investigation after a fire on his farm, has died of an apparent self-inflicted gunshot wound, authorities say.

Mechtel, 39, of Page, was an unsuccessful Republican candidate for the U.S. House in 2006. He also was a former chairman of the North Dakota Soybean Council and the Northern Crops Council.

Cass County Chief Deputy Jim Thoreson said Mechtel was found dead Thursday morning by family members at his family farm near Page.

"We had a call at about 10:55 this morning that a male shot himself with a shotgun," Thoreson said. "It appears to be a self-inflicted gunshot wound."

Mechtel's farm home near the small town of Erie was destroyed by fire last August. Authorities said no one was there at the time.

Court documents show Mechtel was admitted to a psychiatric center on Nov. 10. He had talked about committing suicide to more than one member of his family, and he was upset because the federal Bureau of Alcohol, Tobacco, Firearms and Explosives was investigating his possible involvement in the fire, the documents say.

"There has been a federal investigation going on regarding Matt Mechtel," U.S. Attorney Drew Wrigley told The Associated Press on Thursday. "But I caution people from drawing any conclusion that may or may not be justified."

Wrigley declined to give details about the investigation.

"When I received word of Mr. Mechtel's death, I hadn't determined what charges, if any, would be presented to a federal grand jury for their consideration," Wrigley said.

Court documents show Mechtel's wife, Denise, filed for divorce in October and a month later, Mechtel's parents, Marvin and Georgie, sought legal guardianship of him, saying their son's "physical and mental health are in serious question."

Mechtel raised corn and soybeans near Page, in northwest Cass County. He also raised elk, and ran a gun shop and a retail tire shop in Page.