It was late Sunday afternoon, Feb. 28, when the team of 10 investigators first moved cautiously into the blast area beneath the World Trade Center, looking for clues to what might have caused the deadly explosion two days earlier. What they found there that day, only minutes after they entered, has proved the key to the case.
The search team, one of two groups that went down that afternoon, was made up of the most senior investigators from the Bureau of Alcohol Tobacco and Firearms and the New York City Police Department's Bomb Squad. Two were bomb squad detectives; the eight others were from the ATF - two explosives technicians, each with a military explosives background, two forensic chemists and four crime scene investigators. Their mission: to do swabbings and to find areas that would be good for locating evidence.Armed with flashlights, a camera and evidence collecting kits, the group headed directly for level B-2, near the ramp to B-1 - the area directly beneath the ballroom of the Vista Hotel where the blast had left a huge hole. This, according to investigators who were at the site that day, was the most likely site to have been the bomb's origin.
Moving through piles of mangled vehicles, ducking pipes and beams that had fallen in the blast, they scanned the heaps of debris, they looked for heavily damaged and blasted car parts - the most obvious evidence of a vehicle that might have held a detonated explosive.
Investigators, who insisted they not be identified, said that as the group of 10 broke apart to explore, four investigators, including the two ATF bomb experts, Joseph Hanlin and Terry Byer, ATF agent Kevin Washington and police bomb squad detective Donald J. Sadowi, moved across the B-2 floor near the crater.
A large, grossly mangled piece of metal lying in pile of debris on the ramp caught the beam of one of their flashlights. Hanlin, the bomb expert, kneeled down, picked it up and turned it over. It was a piece of a heavy frame - clearly, the investigators agreed, part of a truck or van. Inspection of the piece revealed a series of numbers stamped into the metal - numbers that could be used to trace vehicle.
"This is something we need to take," Hanlin told the others, who quickly agreed.
The piece of frame, or chassis, was carted out on a gurney. It was one of less than a dozen pieces that came out that afternoon - all bits of what investigators later determined was a Ford Econoline van that had been rented from a Ryder rental company in Jersey City and later reported stolen.
During the two hours, other investigators, including John Goetz and David Sherman, found other pieces of shattered metal, each with part identification numbers that later were traced to the van. At about 5:30 p.m., the group emerged from the garage, having been warned that the chunks of concrete had ot yet been stabilized, and they turned their evidence over to laboratory tech-ni-cians.
The next day, almost certain that the mangled piece of frame would prove invaluable, one of the investigators went to the laboratory and extracted the number himself. He then turned it over to the Federal Bureau of Investigation, which tracked the part to a rental van, and finally to New Jersey and Mohammed Salameh, who was arrested on Thursday and charged with participating in the bombing that left five dead and more than a thousand injured.
In the four days between that initial discovery, the 10 investigators were reassigned to other, smaller teams to continue probing the site. The principal evidence, however, had been found.