After a painstaking five-day search that held the nation spellbound, the bodies of John F. Kennedy Jr., his wife, Carolyn Bessette Kennedy, and her sister, Lauren Bessette, were recovered Wednesday off the coast of Martha's Vineyard.

After the recovery, sources close to the Kennedys said that the family requested a burial at sea. The Coast Guard said Kennedy's remains will be buried at sea Thursday morning.

A mass for Kennedy, 38, and his wife, 33, will be said Friday at St. Thomas More Roman Catholic Church in New York City, the place where his mother, Jacqueline Kennedy Onassis, attended church.

A private memorial service for Lauren Bessette, 34, will be held Saturday in Greenwich, Conn., her hometown.

The Bessette family also was planning a burial at sea for the two sisters, according to reports.

President Clinton, who will attend the Kennedy service with First Lady Hillary Rodham Clinton, on Wednesday defended the resources that were committed to the rescue and recovery efforts after Kennedy's plane crashed Friday night on a flight from New Jersey to Martha's Vineyard.

"If anyone believes that was wrong, the Coast Guard is not at fault, I am," Clinton said. "It was because I thought it was the right thing to do under the circumstances."

The Kennedy family was notified of the discovery of the wreckage early Wednesday morning. The Coast Guard flew Sen. Edward M. Kennedy (D-Mass.) and his two sons, Rep. Patrick Kennedy (D-R.I.), 32, and Edward M. Kennedy Jr., 37, to Martha's Vineyard to identify the bodies.

The bodies were then taken to medical examiners at Woods Hole, a port on Cape Cod. At about 8 p.m. Wednesday the remains were being prepared for return to their families.

Federal investigators gave the following account of the discovery of the ill-fated craft and the bodies:

The wreckage of the single-engine Piper Saratoga II HP airplane containing a body believed to be that of Kennedy was spotted around 11:40 p.m. Tuesday by a camera-equipped remote operating vehicle, known as an ROV.

At 6:30 a.m. Wednesday, the Coast Guard sent down two ROVs to scan the crash site. At 10:30 a.m. the first divers identified the three victims. National Transportation Safety Board officials said the wreckage containing the three victims' remains were found less than half a mile from the estimated impact site.

The discovery occurred after the research vessel, named Rude, painted a three-dimensional map of the ocean bottom, creating high-resolution images. The recovery was aided by radar-data calculations, performed by the safety board, that determined the aircraft's "splash point."

Divers found all three bodies in or near the fuselage in waters 116 feet deep and seven miles off the coast of Martha's Vineyard, near the town of Aquinnah. The plane's wreckage was strewn over a 100-square-yard area of the ocean floor.

The divers saw "twisted wreckage, wires, seats, the kind of things you could imagine that would be the result of an high impact at water," said Coast Guard Rear Adm. Richard Larrabee.

He added that an 8-to-10-foot portion of the fuselage had been recovered, which had the plane's serial number, N9253N. The plane's wings and engine had been separated from the fuselage, suggesting a violent impact. Officials from the safety board and the Federal Aviation Administration have said the plane was descending at a rate of more than 5,000 feet a minute at the time of the crash.

A "water ram" effect equivalent to the force of 2 pounds of TNT exploding was likely unleashed when Kennedy's plane hit the water's surface, according to Dale Ridder, a marine forensic expert. Ridder, a member of the Marine Forensic Panel, based his assessment on FAA radar data showing the plane's rate of descent, estimated speed, angle of entry and the weight of the aircraft.

"On impact, two jets of water will enter the engine compartment through the cooling air scoops in the nose, and the engine will be driven back into the baggage compartment," said Ridder, a retired Army officer who specialized in marine explosions.

He concluded that Kennedy, his wife and her sister most likely died instantly. Medical examiners performed autopsies on the victims Wednesday night to determine the official cause of death.

In a second dive Wednesday afternoon, divers removed the bodies from the water. The recovery divers were equipped with tools to cut away pieces of the aircraft to extract the bodies from the wreckage, a Coast Guard spokesman said.

The memorial services and funeral arrangements apparently were being made by Sen. Kennedy, the family patriarch since the death of his brothers, President John F. Kennedy and Robert F. Kennedy more than three decades ago.

He also was consulting with John F. Kennedy Jr.'s sister, Caroline Kennedy Schlossberg, and the Bessette family.

A source said the request for the sea burial was made Tuesday when the senator's office contacted the Coast Guard. A Pentagon spokesman confirmed that the family had asked about military burial at sea, an option that would be open to the son of a former president.

A Coast Guard source said the cremated remains were scheduled to be transported out to sea Thursday for a scheduled 9 a.m. EDT ceremony. A family adviser said the burial at sea was designed to avoid having a spectacle made of Kennedy's final resting place.

During his news conference Wednesday, Clinton said the nation should keep its "thoughts with the family as events unfold, and our thoughts and prayers are with them."

At one point, Clinton reminisced about his contact with the young Kennedy, recalling a White House tour he conducted for him. It included a walk through the Oval Office which houses the same desk JFK occupied during his presidency--and the one a photographer captured the younger Kennedy playing in while his father worked at the desk. The tour was one of JFK Jr.'s first visits to the White House since his family moved out after his father's assassination.

Last spring, Kennedy returned as part of a celebration of the U.S. space program. After the ceremony, Clinton took Kennedy and his wife, Carolyn, upstairs to the residence section of the White House.