Bob Whitbeck was almost incoherent when his friends came to his Virginia Beach apartment a few months ago to find out why he hadn't shown up for work. Staring blankly as a video recorder played scenes from "Apocalypse Now," Whitbeck was lost again in memories of a war he couldn't forget.

"He's got something about Vietnam that he just can't shake," said Cecil Perry Jr., a fellow car salesman who took Whitbeck to the hospital that night for fear he might hurt himself or others.

Wednesday, in Arlington National Cemetery, Vietnam was again on Robert K. Whitbeck's mind. There, where generations of war heroes are buried, Whitbeck allegedly held seven military guards hostage at gunpoint at the Tomb of the Unknown Soldier until one of them knocked him to the ground.

"I was going to kill myself and I was going to do it there," Whitbeck later told a Norfolk newspaper in a telephone interview from the National Hospital for Orthopaedics and Rehabilitation in Arlington where he is being held in protective custody.

"No one would believe me about Vietnam," said the 36-year-old former Air Force mechanic who claims he was held a prisoner of war there and has repeatedly petitioned the service for medals he says he earned. "I thought maybe if I killed myself, why I was there would be recognized."

The Vietnam War, his friends say, is clouding Bob Whitbeck's mind like the mist in a steamy Asian jungle. His obsession with it repeatedly has driven him to the brink of suicide, they say.

His wife, Dorothy, lost count of the incidents after the time a year ago when she wrestled a revolver from his hand and threw it in the toilet.

This obsession has bankrupted him, as depression and binges with alcohol and pills have cost him one job after another in car dealerships around the Tidewater area.

Described by friends as a clean-cut, warm, friendly man, Whitbeck has been hospitalized repeatedly in the last year for psychiatric problems and has undergone extensive treatment for alcoholism.

"I know Bob real well when he's Bob, and he's the nicest guy in the world," said E.W. Riddick, who worked with Whitbeck in a Norfolk car dealership. "He's a good sales manager, a good worker. He's quick-witted. But when he's drinking he's a different person. He doesn't even look the same."

"He's a real gentleman," said Tom Barton of Beach Ford in Virginia Beach, where Whitbeck has worked for the past seven months. "Everyone likes him here."

Family members remember Whitbeck as a bright, cheerful youth who excelled in high school sports and enjoyed tinkering with cars.

He enlisted in the Air Force after high school graduation in the mid-1960s and was sent to Vietnam, where he worked as a mechanic on C-130 transport planes. Whitbeck reached the rank of staff sergeant and received an honorable discharge in 1970.

Dorothy Whitbeck says her husband will say little about those years, except that he was seized as a prisoner of war when the U.S. base at Kham Duc near the Cambodian border was overrun by the Viet Cong on Mother's Day 1968.

She says her husband told her he was held in a coffin-like box for 13 days, until he overpowered a guard and was able to float down a river on a log to safety.

In all that time, he has told her, his unit did not notice he was missing.

She does not know whether the story is true, nor does she care.

"He's a wonderful man. You won't find anybody better," she says of the man she married in 1980. "I knew he had problems, but I knew he needed someone and I needed him, too."

Whitbeck has repeatedly petitioned the government for a medal recognizing his capture, but even a personal petition to the White House and the head of the Veterans Administration had no effect.

His Air Force file, said a federal official familiar with the case, carries no indication that Whitbeck was ever captured or saw combat. "My goodness, if someone does something we would want him to get recognition," the official said. "But there's just no record of it."

Over the years, Whitbeck grew despondent more and more frequently. Dissatisfied with the treatment he was receiving at the Veterans Administration Hospital in Hampton, he turned to a private psychiatrist, but nothing seemed to ease his pattern of binge drinking and suicide attempts.

Last July, he took an overdose of pills and alcohol in a Norfolk motel, then called friends at a local auto dealership to tell them he was ending his problems. They kept him on the telephone long enough for law enforcement authorities to find him.

A few months earlier, when Mrs. Whitbeck was hospitalized for back surgery, she was informed by a doctor that her husband was in the intensive care unit after trying to kill himself.

Dorothy Whitbeck said she thinks her husband was intent on suicide when he left their apartment for the office Monday morning and instead wound up in Washington.

He called her four times over the next two days, almost in tears, refusing to tell her where he was.

"I knew he was thinking of suicide because he said he wasn't going to live any more and disappoint people any more, especially me," she said. "I said, 'Forget the past, think about the future. Think about us.' "

By Wednesday evening, Bob Whitbeck was hospitalized again, this time under the scrutiny of an armed guard, his demons subdued at least for the moment.

"He was reaching out for help, and he was reaching out in the wrong way," Dorothy Whitbeck said. "But some people just don't know how to reach out."