EDMOND, Okla. — Police hoped to interview about a dozen students of a local karate studio Friday after riding on the Fourth of July parade float driven by a man who accidentally ran over and killed his 8-year-old son.

No charges are expected to be filed against Quinton Hooper, 44, who was driving the float to a staging area after participating in Edmond's LibertyFest Parade when his son, Aidan Hooper, either fell or jumped from the float, Police Officer James Hamm said.

"The hard thing in this case is that most of the witnesses were young children, so we're having to speak with their parents to get a good idea of whether he jumped off or fell somehow," Hamm said. "That's the main thing we're trying to determine.

"We're having to be sensitive to the fact that these are young children."

Police interviewed Quinton Hooper, but a final report on the accident will not be completed until investigators determined who was on the float and spoke to them.

The flatbed trailer — decorated with red, white and blue ribbons and loaded with hay bales — knocked the child to the ground and ran over him, Hamm said. As many as 20 or more people, including many young children outfitted in karate uniforms, were aboard the float, and several others were walking behind it when the accident happened.

A nurse and a police officer performed CPR on the boy until he was transported by ambulance to a hospital in Oklahoma City, where he was pronounced dead. The medical examiner's office had not completed an autopsy on the boy late Friday afternoon, and the cause of his death had not been officially determined, spokeswoman Amy Elliott said.

Parents comforted their children Friday outside the ATA Karate and Life Skills Training Center in Edmond, a suburb of about 80,000 just north of Oklahoma City. Employees at the center declined to speak to reporters. Aidan Hooper was a student there, Hamm said.

City officials in Edmond said a special events committee that works with parade organizers are expected to review their policies and procedures to ensure the safety of future events, city spokesman Casey Moore said. Three Edmond high schools and a local university each host smaller homecoming parades, and the city hosts a Christmas parade in December, Moore said.

"We feel like the parades are safe, but with an incident like this happening, it always is worth taking another look," he said.

Telephone and email messages left with the organizers of Thursday's parade were not returned.

LibertyFest, an annual tradition in Edmond for more than 40 years, is the largest single event in the city and attracts more than 50,000 people. The event takes place over two weeks and includes a car show, road rally, concert, rodeo, parade and fireworks display.