LaMOURE, N.D. (AP) - A man accused of killing a LaMoure County farmer seven years ago in a dispute over water drainage has pleaded guilty to manslaughter and agreed to help authorities find the body.

Steve Thomas, of Fargo, pleaded guilty Friday in the death of Norman Limesand, 82, of Marion, a neighbor, who disappeared on Nov. 12, 1999. Authorities said the two had argued that day.

"After seven long years, it's time to get this finished," Assistant Attorney General Jon Byers, who helped prosecute the case, said in court Friday. "Mr. Thomas is the only one still alive who knows why he did what he did and what he was thinking when he did that."

Judge James Bekken did not immediately set a sentencing date, but said he expected it would be in early January.

Limesand's bloodstained truck was found abandoned in Moorhead, Minn., four days after he disappeared, but his body never was found. He was declared dead in 2002.

Thomas, who had been working as a truck driver out of state, was charged with murder in August last year.

Thomas' mother, Bonnie Rosland, was sentenced to five months in jail for lying to a grand jury about her son's whereabouts on the day Limesand disappeared. Authorities said Limesand's eye glasses and traces of his blood were found on an approach to the farm that Thomas and Rosland shared, about 2½ miles from Limesand's home.