It had to be an accident.
Hard to imagine now, but that was the prevailing theory moments after an explosion rocked the World Trade Center around noon on a chilly Feb. 26, 1993.
The truth -- that a cell of Islamic extremists had engineered a car-bomb attack that killed six people, injured more than 1,000 and caused more than a half-billion dollars in damage -- "was incomprehensible at the time," recalled FBI agent John Anticev.
On the eve of the 20-year anniversary of the bombing, Anticev and other law enforcement officials involved in the case reflected on an event that taught them tough lessons about a dire threat from jihadists. That threat, now seared into the city's psyche because of Sept. 11, felt vague and remote two decades ago.
The scale of the attack was the first demonstration that "terrorism is theater and New York is the biggest stage," said Police Commissioner Ray Kelly. He was serving his first stint as commissioner when the initial report to police that day was that there was an apparent transformer explosion at the trade center.
Kelly raced to the scene, where a bomb in a parked Ryder van had left a crater half the size of a football field in the trade center garage. "I remember seeing this tremendous sea of first-responder vehicles . . . and smoke was coming out," he said.
Kelly gathered with other police and federal officials in a nearby hotel conference room to assess the damage. The meeting didn't last long because an engineer warned "the floor could collapse at any time," Kelly said.
A day later, after a utility mishap was ruled out, authorities "started to come to the conclusion it was bomb," he said.
Anticev and other FBI agents were initially assigned to pursue rumors that the Twin Towers may have been attacked in retaliation for the U.S. bombing of Serbia. But the probe took a dramatic turn after investigators found a vehicle identification number on a piece of the blown-up van.
Investigators learned later that the renter of the van wanted to get his deposit back after reporting it stolen -- a break that sounded too good to be true.
"I was betting he wouldn't show up," said Kelley.
The renter, Mohammed Salameh, indeed appeared to demand his deposit about a week after the blast.