An 82-year-old Bladensburg man with no history of serious mental lapses vanished from the yard of his home Tuesday, baffling relatives and police, who have found no trace of him despite a wide search.

William Bergstron of 4901 56th St., described by a nephew as "mentally sound and very alert for his age," stepped out of his house to look at the engine of his pickup truck late Tuesday morning, according to Grace Bergstron, his wife of 46 years.

When he did not return after a few hours, she said, she walked outside but could not find him.

Bladensburg police Lt. Charles Owens said about 30 officers, firefighters and volunteers searched dozens of acres of woods near Bergstron's house until well after midnight, but found no sign of him.

The search resumed about 8:30 a.m. Wednesday, involving dogs and a helicopter, but it was called off at midafternoon, Owens said.

"We know of absolutely no reason why Bill would have left voluntarily," said Owens, who is continuing an investigation. "And we know of absolutely no motive for foul play."

A nephew, James Maness of Memphis, one of several out-of-state relatives staying with Grace Bergstron since her husband's disappearance, said family members plan to begin distributing fliers bearing Bergstron's photograph.

Bergstron, who retired in 1969 as a civilian clerk for the Coast Guard in Washington, had a heart pacemaker implanted two years ago, but remained physically active, Maness said.