By the time Mr. Martin was taken outside by the agents, he was handcuffed, Mr. Bennett said. The agents kept Mr. Martin, who was wearing a T-shirt and shorts, outside his home for several minutes before taking him away.

Another neighbor, Dawn Dincher, 43, said she worried that Mr. Martin, a tall, stocky man, might have had a heart attack. “He was so pale in the face after it happened,” she said. “He obviously looked scared to death.”

The subsequent F.B.I. search lasted for hours. “I happened to get up to go to the bathroom around 3 or 4 o’clock in the morning. They had a couple of vans and were putting stuff in there,” Mr. Bennett said. Agents had illuminated the yard with floodlights and set up tables to spread out and examine the items they were confiscating.

Mr. Martin, whom friends called Hal, has not been back since. He is being held in federal custody, charged with theft of government property and unauthorized removal or retention of classified information as investigators try to determine why he had top-secret documents in the house and in his blue Chevrolet sedan.

An intelligence official involved in the investigation called it “a sad case.” There is no public evidence so far that Mr. Martin passed classified information to anyone else, though without his cooperation, it could be difficult to determine whether he had shared anything.