ROANOKE TIMES
Copyright (c) 1996, Roanoke Times
DATE: Saturday, August 24, 1996 TAG: 9608260042
SECTION: NATIONAL/INTERNATIONAL PAGE: A-1 EDITION: METRO
DATELINE: SMITHTOWN, N.Y.
SOURCE: Los Angeles Times
THE FBI announced that the microscopic traces found on TWA Flight 800 wreckage are not conclusive.
Federal law enforcement officials announced Friday that ``microscopic explosive traces'' of some kind of a bomb or missile have been found on part of the wreckage of TWA Flight 800, but they cautioned that the residue is not enough to tell investigators how or why the jumbo jet carrying 230 people exploded last month in the skies off Long Island.
``Based on the evidence to date,'' said James Kallstrom, head of the FBI's field office in New York, ``investigators cannot conclude whether this tragedy was the result of a criminal act.''
The residue is still being examined by forensic experts.
Kallstrom declined to provide details on what kind of residue was found. But other federal law enforcement sources, speaking anonymously, said it was traces of PETN, a potent plastic explosive component that has been used in the past both in airplane bombs and surface-to-air missiles.
They described the amount of PETN (short for pentaerythritol tetranitrate) uncovered in the FBI's Washington laboratory as no larger than a ``speckle.'' They said it was found on a piece of seating material on the right side of the plane's middle passenger compartment, between Rows 17 and 28.
That area of the plane - the central fuselage - has become for investigators the most likely spot where the explosion originated, whether from a bomb, a missile strike or a mechanical failure.
Appearing at a hastily called news briefing to refute rumors that the FBI now considered the disaster a criminal act, Kallstrom departed from his normally low-key attitude and read a carefully written statement he hoped would tell the U.S. public exactly where the investigation stands.
``As a result of scientific analysis conducted by federal examiners, microscopic explosive traces of unknown origin have been found relating to TWA Flight 800,'' he said.
``However, based on all of the scientific and forensic evidence analyzed to date, we cannot conclude that TWA Flight 800 crashed as a result of an explosive device.
``Forensic experts outside the government, consulted by the FBI, agree that the detection of the microscopic explosive traces alone does not allow the conclusion that TWA Flight 800 crashed as a result of an explosive device.''
He said more corroborative evidence must be found, none of which has yet been detected after more than 60 percent of the plane's wreckage has been recovered from the ocean floor.
``For example,'' he said, ``physical damage or patterns characteristic of a detonation would need to be available, in addition to confirmed explosives as trace findings, before a positive conclusion of an explosive device could be made.''
That description compares with those of the two law enforcement sources, who cautioned that PETN could have come from the clothing of a hunter, soldier or quarry worker - indeed, from anyone who might have come in contact for whatever reason with explosive material before boarding the plane.
They said it also could have come from Navy equipment used to hoist the wreckage out of the water and transport it back to land. But Rear Adm. Ed Kristensen, who is overseeing the Navy salvage operation, said there was no residue on either of two large Navy ships ``that could have contaminated anything.''
In addition, the sources said it is perplexing that only a small piece of PETN was found, because a bomb or missile explosion should have left behind more and larger splotches of the explosive material.
``Any time you find minute traces of chemical, you can't jump to conclusions,'' said one of the sources, a senior law enforcement official. ``There are a lot of things that could have contaminated the evidence.''
The 747 jetliner exploded shortly after takeoff as it climbed past 13,000 feet on the evening of July 17. All but 20 of the victims have been recovered.
Experts said explosives made from chemicals such as PETN are attractive to terrorists for several reasons. They create a larger explosion than a similar amount of nitroglycerin or TNT. They are safer to transport because they are not easily detonated. And they give off fewer vapors, making them all that harder to detect.
The material generally cannot be detected by airport inspection devices, particularly those in the United States that do not have the more elaborate high-tech systems found in Europe.
Plastic explosives were developed during World War II. Today, in the right hands, they can be made to look like bricks, shoe leather or even Silly Putty.
Vince Cannistraro, a former CIA counterintelligence operations chief and lead CIA investigator in the bombing of Pan Am 103 over Lockerbie, Scotland, said of PETN, ``A small quantity is all that would be needed - a few pounds - to blow up a 747.''
In the case of the TWA flight, he said, someone ``could take it in on handcarry [luggage] and assemble the bomb on board, then put it under your seat.''
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