Getting your Trinity Audio player ready...

Searchers on Saturday found a milelong trail of debris on the ocean floor off Long Island leading to what could be the fuselage of TWA Flight 800, potentially the most important piece of evidence in the quest to determine whether a terrorist bomb downed the jumbo jet and killed all 230 people on board.

Robert Francis, vice chairman of the National Transportation Safety Board, said the wreckage was located by U.S. Navy and New York City police searchers on vessels that were scouring the area where the Boeing 747 was believed to have entered the water after the jet exploded in a giant fireball Wednesday evening.

As the investigation continued, police flew members of the families of several victims to the site of the wreck. After some pressure from the FBI and New York governor’s office, the size of the medical examiner’s team working on the remains was expanded and put on a 24-hour schedule. The Navy and Coast Guard were pressed to step up the pace of the search for wreckage.

Grieving and frustrated relatives of the crash victims told officials they were growing increasingly anxious to claim the remains of their loved ones. Some charged that the FBI was withholding information or that resources had been drained by the Olympics in Atlanta.

“We want the wreckage off the floor for forensic evidence. The families want it because they want the bodies for closure. I am harassing the hell out of them to get that stuff off the sea floor,” said James Kallstrom, head the FBI’s New York office and director of the investigation.

While Francis and FBI officials visited with relatives of victims in a bid to ease their concerns, there were a number of signs that the investigation was moving toward the conclusion that it was a bomb that brought down the plane, a well-maintained jet that had no record of any particularly serious mechanical problems.

Senate Commerce Committee Chairman Larry Pressler (R-S.D), briefed regularly by the FBI, said the investigation “seemed to be moving” toward that result. Kallstrom, an ex-Marine and Vietnam veteran with a reputation for tough talk, said it was unlikely that a mechanical failure caused the blast, although he sharply criticized the media for leaping to conclusions about the case.

“I know there was a catastrophic event on the airplane. The least likely thing is mechanical,” said Kallstrom, whose professional interest in the crash was mirrored by a personal interest: a friend of 25 years, one of the flight crew members, was killed.

But he said he was still waiting for evidence that would present some proof of what happened, or a confession from someone responsible.

“Without some forensics or some other evidence that comes our way, the golden nugget, somebody comes in and confesses and we corroborate his story . . . we’re not going to get there,” he said.

The Paris-bound airliner was still in its climb to cruising altitude when it was ripped apart by a massive explosion that created a huge fireball witnessed by thousands of vacationers and residents on Long Island. Wreckage continued to wash ashore Saturday. Less than one percent of the huge plane has been recovered, according to Francis.

Investigators have poured over the maintenance records of the plane and the flight records of its pilots, both 30-year veterans with thousands of hours in TWA cockpits.

Authorities have reviewed radar tapes to check on rumors a missile may have been fired at the plane. U.S. security officials also have reviewed security procedures and interviewed airport personnel in Athens, the doomed plane’s last stop before it went to New York.

But investigators’ greatest interest has been in the biggest part of the plane that was likely to have survived the crash, the center section of the fuselage, heavily built and reinforced because of the placement of the wings. The fuselage also includes a big cargo hold.

Authorities believe this also is the part of the plane most likely to contain remains of passengers still strapped into their seats, which could provide crucial evidence about what happened. Medical examiners will look for shrapnel-like shards of metal that could indicate an onboard explosion. Nothing like that has been found among remains yet.

Francis and Kallstrom characterized the discovery of the wreckage in about 100 feet of water as “heartening” news, because if the hulk is the 747 fuselage, investigators will have their first look at parts of the plane that would have been most affected by an on-board bomb.

Kallstrom indicated Saturday that the FBI had already collected what it considered to be valuable evidence from the remnants of the plane and from the blast victims’ remains, but he refused to discuss them and said he wouldn’t talk about evidence until it led to some clear conclusions.

Francis, who denied earlier reports that searchers had heard pinging from locators on the plane’s flight recorders, said the underwater debris was discovered by side-scanning sonar devices and a special towed sonar array that was damaged when it caught on the wreckage.

“There is a trail of material on the bottom and that trail culminates in a large piece of something under there,” Francis said. “It turned out that this piece is 15, or perhaps even more feet off the bottom of the sound. It was sufficiently large that the sonar, which was being trailed behind the boat, got caught up in whatever it is and was damaged.”

Francis cautioned later that investigators still don’t know what the hulk is and that it could be the rusting remains of some World War II-era wreckage, but he and Kallstrom clearly were eager to send divers and video equipment to the spot as soon as possible.

Despite better weather, the seas were too rough Saturday for Navy and police divers, Francis said. A remote-control submarine with television equipment on board is likely to visit the area before divers go down, he said.

“This report is encouraging to us from an investigative standpoint. It is heartening because this is what we want, the fuselage. The rest of the airplane, and something with a higher priority than that. We want the bodies,” said Kallstrom. “I suspect that they are all together. We want the metal so we can look at it forensically.”

If investigators have located the fuselage of the plane, then searchers will move quickly to remove the remains of the victims and raise as much of the wreckage as soon as possible. Medical examiners have said all of the 104 bodies recovered so far were either in the front or back of the plane. Many of the remaining victims are likely to be in the fuselage wreckage.

The FBI also wants to examine the baggage holds of the craft and any evidence on the fuselage that might indicate whether the explosion came from inside the plane–an indication there was a bomb on board–or outside the plane, which could be a sign of some other cause.

Investigators also can conduct forensic studies on metal from the wreckage to see whether it was pitted by an explosion or contains any of the residue from plastic explosives favored by terrorists. Investigators used those techniques to conclude terrorists were responsible for the bombing of Pan Am Flight 103 over Lockerbie, Scotland, in December 1988.

But that kind of study might be hampered if the plane’s wreckage spends too much time in ocean water, which could wash away any explosive residues that might be spotted in chemical testing. Much of the debris collected so far is of little value in such studies, according to the FBI.

While one part of the federal effort focused on searching for the dead and wreckage on Saturday, another turned to the victims’ families. Kallstrom hugged and comforted many of the family members during his briefing for them at the hotel outside Kennedy International Airport where they are being housed.

“This is a period of horrible anxiety for the families,” said Sen. Alfonse D’Amato (R-N.Y.), who attended the briefing. “It’s taking a tremendous toll on them. They broke down in Kallstrom’s arms. They shared grief and anguish. They have all sorts of questions: Is information being withheld because of the Olympics? Are sufficient resources being utilized?”

Kallstrom said later that he told the families that this is the first time in his 26-year career as an FBI agent that he has been told to ask for anything he wants or needs to conduct his investigation.

He said the Olympics are in no way compromising the TWA Flight 800 investigation, that he has all the resources he needs, everywhere in the world, and can ask for more at moment’s notice.

“I tried to explain to them. I told them I knew they weren’t that interested in who did this right now, but they may be interested in that later,” Kallstrom said. “What they were really interested in is getting the bodies of their loved ones back. That was rammed home again and again and again.”

The veteran agent, a master wiretapper and surveillance expert who has been close to the heart of every major FBI organized crime and terrorism effort for years, said he told the families he shared their interest.

“I told them I was there to be their advocate,” he said, “That I wanted the fuselage, too, be it for other reasons. I want it for their reason also. I told them of the tragedy that one of the people on that fuselage is a friend of mine.”