Authorities are investigating how a farmer in Oregon managed to be eaten by his own hogs.

A family member found what was left of Terry Vance Garner, 69, when they went to look for him a few hours after he'd left to feed his hogs — some of which weigh more than 700 lbs.

"For all we know, it was a horrific accident, but it's so doggone weird that we have to look at all possibilities," Coos County District Attorney Paul Frasier told the Register-Guard newspaper.

Frasier said the family member first noticed Garner's dentures at the farm's hog enclosure, then saw pieces of the man scattered around.

The district attorney said Garner may have simply keeled over from a heart attack while feeding the animals. Then again, perhaps the hogs knocked him down, killed him and ate him, he added. There had been reports of the hogs behaving aggressively towards Garner before, even biting him once.

Or maybe someone else killed Garner and let the hogs dispose of the body. Frasier said he is also investigating the possibility of foul play.

Garner's brother Michael said the old farmer loved his animals, which he'd had since they were piglets and which helped him deal with his post-traumatic stress disorder from the Vietnam war.

Michael said a sow bit Terry once, but only because he accidentally stepped on its piglet, killing it.

"He said he was going to kill it, but when I asked him about it later, he said he had changed his mind," Michael told the paper.

John Killefer, who heads the Animal and Rangeland Sciences Department at Oregon State University, said killer hogs are unusual but not impossible, noting they "are more omnivorous than other farm animals."