But they were getting very close. Privately, most investigators were convinced that Flight 800 was brought down by a bomb planted somewhere in the midsection of the 747 jumbo jet, probably near the right wing (chart). The missile theory just didn’t stand up to scrutiny, and possible causes of mechanical failure had been ruled out, one by one, until few, if any, were left. Even without a formal finding that a bomb had been planted on the plane, the FBI had begun a vast manhunt for the bombers. And NEWSWEEK has learned that a team of federal prosecutors has been working with the FBI agents all along, carefully laying the groundwork for an eventual prosecution.
So what was the FBI waiting for? Without a finding that a crime was committed, the investigation was still formally led by the National Transportation Safety Board (NTSB), an agency whose open and deliberative institutional culture clashed at times with the tight-lipped, hard-charging style of the FBI. After The New York Times broke the story of the PETN discovery, Kallstrom said at a news conference that more evidence was required to establish that a crime had occurred. In- vestigators were looking, among other things, for ““microcratering,’’ a type of pitting in the metal caused by jets of hot gas or by small particles moving at high velocity. Pitting could establish that a bomb went off, but so far, only a few ““false Eurekas’’ had been found, Kallstrom told NEWSWEEK. Decisive evidence could still turn up. Kallstrom said that within three weeks, the navy expects to finish recovering all the wreckage that can be retrieved.
Hope was fading that forensic evidence of a bomb blast might be found in bodies newly recovered from the ocean. By late last week, 208 of the 230 passengers had been found and identified, with no report of visible bomb damage. The remainder may not provide much evidence; bodies that stay in the water longest naturally show the most deterioration. Divers have been bringing to the surface corpses nibbled by marine life, hugging the skeletons in a sad embrace as they rise from the depths. So much tissue was missing from those bodies that fingerprints were no longer useful for identification. Instead, investigators had to rely on dental records or DNA analysis, using blood samples from relatives. Medical examiners also had to cope with a number of severed body parts, including one head, that had not yet been matched to corpses.
Kallstrom, who lost an old friend in the crash, said he hopes it was caused by something other than terrorism. ““The FBI is not rooting for a bomb,’’ he said. ““The best thing for the country, and probably the world, is a mechanical failure.’’ So far, however, none of the mechanical theories has panned out. The cockpit voice recorder showed no sign of the crew’s attempting to cope with a breakdown, and the four engines revealed no mechanical failures. For the first time, Robert Francis, vice chairman of the NTSB, confirmed publicly that there had been an explosion in the center fuel tank, but how it occurred was still officially a mystery. Investigators said a slight chance remained that the blast might have been caused by a malfunction in a fuel pump. That possibility will be examined this week, when parts of the plane are tested at a NASA facility in Huntsville, Ala.
The presence of PETN kept alive – just barely – the theory that the airliner might have been shot down by a missile. The compound is commonly used in the warheads of surface-to-air missiles, and some eyewitnesses reported seeing streaks of light approach the plane before it blew up. But many antiaircraft missiles are heat-seekers, drawn to their targets by engine exhaust. The state of the engines all but ruled out a missile as the cause of the crash.
PETN (pentaerythritol tetranitrate) is a common ingredient in many explosives, including terrorist bombs. It was used in the destruction of Pan Am Flight 103, which exploded over Scotland in 1988, killing 270 people. The presence of PETN on TWA 800 was first detected by explosive-sniffers a few days after the crash. That result could not be confirmed by the FBI lab, perhaps because the initial test consumed the sample.
It is conceivable – but only barely so – that minute traces of the chemical might have been carried onto the plane by a passenger on an earlier flight: a military man, for example. More likely, investigators say, the PETN was part of a bomb concealed in the passenger compartment. Several other possible sites have been eliminated, including the cockpit, the forward cargo hold and the galley nearest the explosion. The plastic explosive may have been left under a plane seat, perhaps molded into the lining of a carry-on bag.
That was the technique used in bomb attacks against a Pan Am airliner in 1982 and a TWA plane in 1986. Five passengers were killed, though both planes landed safely. A Palestinian group called the May 15th Organization (named for the day in 1948 when the state of Israel was established) was blamed for the attacks. Now the FBI is scrutinizing every terrorist group known to have targeted Western airliners, many of them Middle Eastern and some linked to Iran. But there is no indication yet that the FBI is focusing on any particular group or individual in the TWA 800 crash.
All told, the FBI has 300 to 400 agents in the field, looking for answers. They know that eventually they will have to interview the families of victims, and they dread the tough questions they will have to ask. Did anyone recently take out a large life-insurance policy? Did anyone have friends who were hostile to the United States? Did anyone carry onto the plane a gift from someone else? Such questions can only add to the pain of people who have suffered too much already. But they have to be asked if a bomber is to be found.
