Debris flew into the grandstands at a monster truck show in Washington state, killing a 6-year-old boy and injuring another spectator, witnesses and city officials said Saturday.

A red truck came apart while doing doughnuts during the freestyle competition of Friday night’s Monster Jam show, the witnesses said. Debris from the truck flew 30 to 50 feet over a safety barrier into the stands.

‘‘Parts were falling off and a piece flew up and hit a little boy,’’ Christine Moe told King Television of Seattle.

Police Officer Mark Fulghum said officers serving as security at the Tacoma Dome investigated the accident.

‘‘At this point, there’s nothing to indicate that there’s anything criminal,’’ Fulghum told The Associated Press on Saturday night. ‘‘Right now it looks like a tragic accident.’’

The Pierce County medical examiner’s office identified the boy killed as Sabastian Hizey of Puyallup.

The boy’s father, Jessie Hizey, issued a statement to KIRO-TV on Saturday that said his son was hit in the head by a Frisbee-sized piece of metal, weighing between 7 and 12 pounds.