Investigators examined bits of the drive train from an oversized truck this weekend to try to find out why a Frisbee-sized chunk of metal tore loose and hit some in the spectators, killing a 6-year-old boy, Sebastian Hizey, and injuring another person at a Monster Jam truck show in the Tacoma Dome.

Bill Easterling, senior operations director for Feld Motor Sports of Aurora, Ill., said on Monday that the police had gathered loose parts of the drive train and the drive train loop, a special monster truck device that is supposed to hold the drive train on the vehicle.

He declined from giving any further information like the description of the loose parts and where they were found. "I've never seen the loop or the drive shaft parts come off like this," said Easterling.

Monster truck shows have been a crowd puller at the Tacoma Dome for more than 20 years. They feature vehicles weighing 9,000 pounds or more and equipped with
5-foot tires.

The spectators, however, thought of this incident as a freak accident and said that they had no qualms regarding their safety at the show.