David was the Kennedy with the most to prove. Part would-be intellectual, part high-living playboy, he had yet to make his mark anywhere but at Manhattan discos. He bounced through two colleges and a series of short-term jobs. At 24, still lacking an undergraduate degree, he was haphazardly pursuing writing projects, living in a rented New York co-op, talking vaguely about going back to Harvard. Then his confused—but hitherto mostly private—struggle to define himself went public with startling suddenness. On a humid September evening police from Manhattan's 28th Precinct responded to an emergency call from a seedy Harlem hotel. They found David Anthony Kennedy dazed and bruised in the lobby. Scattered on a third floor landing were 25 packets of heroin—and the life of the third son of the late Sen. Robert F. Kennedy became a matter of clamorous public interest and frantic family concern.

The story emerged layer by layer—the first offered by David himself through a police spokesman. He said that he had been driving along West 116th Street—a bleak urban crimescape far off limits to the affluent and white—when two men signaled from the curb. He said he pulled over to see what they wanted, then followed them into the sleazy Shelton Plaza Hotel, where they robbed him of $30 and beat him. Later police sources said David had actually been trying to buy cocaine—a high-priced drug well beyond the reach of the nodding losers who populate the notorious Shelton Plaza. Finally word leaked that David had been trying to buy heroin—and had confessed to police: "I'm a stoned-out junkie."

The leak was promptly plugged, and the NYPD refused to confirm or deny the story. "Police here know you don't mess around with Kennedys," said one source inside the department, rankled at the nervousness among higher-ups. Still listed as a victim of whatever happened at the Shelton Plaza, David was never arrested. But even the family admitted that he was in grave trouble, and they could not hide their anxiety. "He is physically sick," his older brother Robert Jr. said cautiously. "He is receiving medical care." In a less-disciplined moment he confessed: "I'm shocked by all this. It's a big family—people take different paths. But David is very bright and really, really sensitive."

In the aftermath, what exactly happened to David in Harlem and his prognosis for recovery were eclipsed by a larger question. As the Shelton Plaza day manager, Cassandra Brown, put it: "This boy has all the money in the world. Why should he come up here?"

The search for an answer focused on the central trauma of David's young life: his father's assassination when he was 12 years old. Earlier on that June day in 1968, while swimming off Malibu, David had been pulled far out to sea by the undertow. He floundered, near drowning, until his father, striking out from shore, managed to reach and save him. Only hours later, as David sat up late in his hotel room recovering from the ordeal, he watched his father's televised speech at the Ambassador Hotel in Los Angeles—and then, in horror, his murder. Author Theodore White ran to David's room to turn the television off, but he got there too late.

Even before that David was known as "the difficult one" of Bobby and Ethel's 11 children. He compiled a history of vandalism near the family's McLean, Va. home and later run-ins with the law for speeding, reckless driving, using unregistered cars and driving without a license. (Even the BMW he drove to Harlem had expired Virginia plates and four unpaid parking tickets in the glove compartment.) David's first reported use of narcotics resulted from a family jeep accident in 1973. It left a Cape Cod girl paralyzed for life, and he suffered a painful back sprain. As recently as last February he was still taking Percodan, a powerful narcotic, to ease his discomfort.

David's aunt Eunice Shriver not long ago traced the problems of Kennedy children like David to intramural competition in a large and accomplished family. "There weren't any disadvantages being a Kennedy in my generation," she said, "but for the children it may be difficult. It may be tough for them to acquire their own identity. If you have lots of kids, and one of them is going to law school and another has dropped out and another is in college but having a hard time and they hear about each other—that could be a disadvantage." To David, it assuredly was. The oldest of Ethel's children, Kathleen, 28, is married and practicing law in Santa Fe; older brother Joe, 26, is a lawyer and budding politician, married and living in Boston; and Robert Jr., 25, already the author of a book on Federal Judge Frank Johnson, is a student at the University of Virginia Law School.

David, in contrast, dropped out of Harvard in 1976, took a few courses at Boston College, moved to New York to find himself—and found himself in a fast crowd. His main hangout since has been Xenon, a Manhattan disco frankly aimed at the rich preppie crowd. Otherwise, his New York life has been rootless. For a while he said he was researching an article on Urban League director Vernon Jordan, but he never interviewed Jordan and the article remained unwritten. David talked of working on a newspaper for six months and then returning to Harvard, but he never got the job or made much attempt to. His habits were sloppy, his dress ran to old jeans and rumpled shirts. Model Rachel Ward, 21, his girlfriend for five months this year, was a frequent visitor to his rented penthouse on East 72nd Street and shared his nights at Xenon. She acknowledges that "we smoked joints now and then, but there was no suggestion of heroin." She adds, with affection: "He ate like a pig and didn't take very good care of himself, but he was crazy, with a wonderful sense of humor, and he was always very merry."

Yet he remained a Kennedy, and watching his peers barrel purposefully into the future could not have left him entirely comfortable with his idle life. "He talked about Teddy and his father and his family in a happy way," says Rachel Ward, but the inevitable comparisons were painful. The front page of the Boston Herald-American ironically captured the torment of his life in the shadows two days after his Harlem escapade. KENNEDY FAMILY GIVES TED THE GREEN LIGHT TO RUN FOR PRESIDENT, trumpeted the lead headline. Six inches below that ran another headline, an appeal from David: "Please...I just want to get back to Hyannis."

Sources close to the Kennedys agree that going home is not an option—family disappointment and worry might only magnify his troubles. They put their hope in professional treatment, speculating that David wanted to be stopped—how else to account for his inexplicable visit to Harlem? (Some residents said he had been there before.) But if being a Kennedy helps explain his default, it may also be providential. He faces a major crisis with the unstinting support of a tight-knit, loving family—and with the best wishes of devoted friends, who will perhaps understand better now what it means to be David Kennedy. "He is an awfully nice guy," says Xenon friend Madeleine Fudeman. "Maybe it's better he got caught now, before he is too far gone."