NEW YORK (AP) - Current and former law enforcement officials say that when an explosion rocked the World Trade Center on Feb. 26, 1993, terrorism didn't initially enter their minds.
The first report that day suggested a possible transformer mishap. But investigators learned over the next several days that Islamic extremists were behind the attack that killed six people and injured more than 1,000.
On the eve of the 20th anniversary of the bombing, the officials said at the time, it was difficult to know whether the attack was an aberration or the harbinger of a global anti-American movement.
The investigation eventually led to the arrest and conviction of the attack's mastermind, Ramzi Yousef.
Yousef is the nephew of Khalid Sheik Mohammed, the self-proclaimed mastermind of the Sept. 11 attacks.