The segment Today broadcast last week ran as “Zimmerman: This guy looks like he’s up to no good. He looks black.” The full conversation ran as: “Zimmerman: This guy looks like he’s up to no good. Or he’s on drugs or something. It’s raining and he’s just walking around, looking about. Dispatcher: OK, and this guy – is he black, white or Hispanic? Zimmerman: He looks black.”

Following a tip, GM hired detectives, searched 22 junkyards for 18 hours, and found evidence to debunk almost every aspect of the crash sequence. Last week, in a devastating press conference, GM showed that the conflagration was rigged, its causes misattributed, its severity overstated and other facts distorted. Two crucial errors: NBC said the truck's gas tank had ruptured, yet an X ray showed it hadn't; NBC consultants set off explosive miniature rockets beneath the truck split seconds before the crash -- yet no one told the viewers. There was plenty of sarcastic speculation about what happened between Monday afternoon, when NBC was defiantly dismissing GM's charges, and Tuesday morning, when it drafted an abject apology largely on GM's terms. NBC News president Michael Gartner says he simply realized that he had goofed by speaking first and asking questions later: ''The more I learned, the worse it got. Ultimately I was troubled by almost every aspect of the crash. I knew we had to apologize. We put 225,000 minutes of news on the air last year, and I didn't want to be defined by those 57 seconds.'' Gartner also faced nonjournalistic pressures. GM's top management had sent word it would sue via the top management of NBC's parent company, General Electric, a big GM supplier. Dateline co-anchor Jane Pauley, who shared the awkward duty of apologizing on air, told the staff in a pep talk the next day that she took ''perverse pride'' in the readiness to admit failings.