TUCSON, Ariz. (AP) – Rodeo parade spectators watched in horror Thursday as a 5-year-old girl was thrown off her mount and trampled by an out-of-control team of horses pulling a wagon. She later died.

Hundreds of people were in eyesight of the tragedy along the two-mile route of the Tucson Rodeo Parade. “People were gasping, screaming,” said Diane Hebert, who was near the scene of the accident.

“I saw the wagon coming around the corner out of control,” said Hebert’s husband, Henry. “They hit the horse, her horse flared up and the girl fell off.”

Hebert said it appeared that two other girls riding beside the 5-year-old saw the horses coming at them and were able to get out of the way. Witnesses differed on whether the wagon ran over the victim.

The girl, whose identity was not released immediately, died at University Medical Center, hospital spokeswoman Darci Slaton said.

Tucson police were investigating, Sgt. Decio Hopffer said.

The death was the first in the parade’s 85-year history, although injuries at the event are not uncommon, parade spokesman Bob Johnson said.

At last year’s parade, Mayor Bob Walkup bruised an arm and his wife, Beth, suffered a concussion and whiplash when two runaway horses slammed into the rear of a 150-year-old buggy.

The parade, billed as the world’s longest nonmechanized parade, includes horses, marching bands, folklorico dancers and beauty queens. It is one of the highlights of the 82nd annual La Fiesta de los Vaqueros rodeo, a weeklong event that began Monday featuring more than 700 contestants from across the U.S. and Canada.