The time, July; the place, off Martha's Vineyard; the name, Kennedy. All were the same. Only the nature of the calamity was different.

In the top photo, Sen. Edward Kennedy's car is pulled from the water in Edgartown on July 19, 1969. Mary Jo Kopechne was killed after Kennedy drove his car off Dyke Bridge on Chappaquiddick Island. Bottom photo shows the bridge as it was reconstructed recently. (AP photos)

The time, July; the place, off Martha's Vineyard; the name, Kennedy. All were the same. Only the nature of the calamity was different.

It was a Friday night 30 years ago, July 18, 1969, that a dark blue Oldsmobile 98 hurtled off a narrow wooden bridge into a tidal pond on the tiny island of Chappaquiddick, adjacent to Martha's Vineyard, killing 28-year-old Mary Jo Kopechne.

The car's owner and driver was Sen. Edward Kennedy, 37, the last of the four Kennedy brothers. The accident became another piece of the Kennedy history of tragedy and ended any hope Kennedy had of becoming president.

The site is only a few miles from where a search continued Sunday for a private plane carrying the senator's nephew John F. Kennedy Jr., his wife, Carolyn Bessette Kennedy, and her sister Lauren Bessette. Authorities conceded late Sunday that John F. Kennedy Jr., his wife and her sister likely were dead.

Martha's Vineyard, an island off Cape Cod, has always been important to the Kennedys as a summer playground. On that weekend in 1969, Ted Kennedy and 11 other people gathered for a cookout at a rented cottage on Chappaquiddick.

All were Kennedy loyalists: five men employed by or friendly with the senator, and six women, "Boiler Room Girls" who had worked in Sen. Robert F. Kennedy's presidential campaign, cut short by his assassination in Los Angeles the year before.

Participants have always said the party was innocent, even though five of the men, including Ted Kennedy, were married and the six women were all single.

All agreed in later testimony that Kennedy and Ms. Kopechne left the party shortly before midnight, saying they were tired, to return to Edgartown on the Martha's Vineyard side of a 150-yard-wide channel.

What happened next has remained in dispute, with an unexplained gap of one hour.

Kennedy said he mistakenly turned right onto a gravel road and skidded off the bridge, the car landing upside-down in eight feet of water. After escaping the car, he tried unsuccessfully to rescue Ms. Kopechne, then staggered a mile back to the party cottage, where he got his cousin Joseph Gargan and friend Paul Markham to return for a second rescue try.

Failing that, they went to the ferry landing, where, they said, Kennedy "impulsively" jumped into the water and swam across to Edgartown, by his own account "nearly drowning a second time."

Gargan and Markham, a former federal prosecutor in Boston, said they assumed that Kennedy, once at Edgartown, would contact the police, and were stunned the next morning to discover he had not done so.

In fact it was a full nine hours -- and after he learned that the submerged car with a body inside had been discovered -- that Kennedy reported the accident to police and said he had been the driver.

At this point the Kennedy clout in Massachusetts kicked in. The other partygoers quickly left the island, and Ms. Kopechne's body was flown by Kennedy-chartered plane to her hometown of Wilkes-Barre, Pa. No autopsy was performed.

Kennedy attended the funeral, with a neck brace he was never seen wearing again.

After a week's silence, holed up at the family's Hyannis compound with such Kennedy "brain trust" figures as Ted Sorenson, Robert F. McNamara and Arthur Schlesinger Jr., he told Massachusetts voters in a televised speech that he had been distraught and confused, wondered if there was a "curse" on the Kennedy family, and asked them to decide whether he should continue in the Senate.

Despite widespread media criticism -- The New York Times said the speech "raises more questions than it answers" and criticized Massachusetts officials for soft-pedaling the inquiry -- aides to Kennedy claimed the public overwhelmingly supported his staying in office. A week after the accident, Kennedy pleaded guilty to leaving the scene of an accident and was given a two-month suspended jail sentence and a year's probation.

Numerous investigations by authors and news organizations spawned a variety of theories, among them that Ms. Kopechne or Gargan was driving the car. But none of these held up under careful analysis.

In 1975, The Associated Press found numerous points of conflict between the sworn testimony of Kennedy and others at a 1970 inquest at Edgartown and a court hearing in Pennsylvania.

The partygoers, most of whom did not know at the time exactly what had happened, have remained all but silent for three decades. Kennedy himself has addressed the subject on occasion without adding new information or clarifying unanswered questions.