Police and city officials in Annapolis are probing the death of a 7-year-old Baltimore boy who was run over by a trailer about to join the annual Independence Day parade.

Investigators want to know exactly how Kyle Aldridge died, said Cpl. Amy Miguez, a spokeswoman for the Annapolis police.

About 7:11 p.m. Thursday, the boy apparently stepped off a trailer being towed by a 2005 GMC van, driven by his grandfather, Jason Hicks, 43, of Glen Burnie, and run over. The boy was taken to Anne Arundel Medical Center, where he died.

A video security system at a nearby business recorded the incident, and the footage is being reviewed, Miguez said.

“It appears that the boy was getting off the side of the trailer at the behest of someone walking along the trailer,” Miguez said.

Investigators are checking reports that the boy’s clothing may have become stuck.

They’ll also determine the weight and speed of the vehicles, likely 2 to 5 mph, to see if those factors contributed to the boy’s death, Miguez said.

With an increased presence of emergency officials for the holiday, a police officer was at the accident scene within one minute and the Annapolis Fire Department arrived within two minutes, Miguez said. “This kid had help there immediately,” she said.

Police do not believe that driver error, drugs or alcohol played roles in the incident. “There’s not really any question of any fault being assigned. It’s an accident, truly,” Miguez said.

On Friday, there were no signs of the accident along Amos Garrett Boulevard, a mostly residential side street where parade participants lined up before embarking on West Street heading toward downtown Annapolis.

Parades in Annapolis are regulated by the mayor’s office. Participants are required to submit an application describing their entry. The city’s rules permit businesses advertising their goods or services to participate, but require their entries to have a patriotic theme.Michelle LeFurge, the city’s events coordinator, said that the owner of the vehicle and trailer complied with all rules and that there were no obvious safety issues.

She said a motorcycle on the trailer, mounted in a wheelie position, appeared to be secured and was not a factor in the accident.

LeFurge said the city has no rules restricting children’s participation in parades.

“Ours is a family and children parade, so their participation — whether they’re in the Annapolis Drum and Bugle Corps or on a float — we enjoy having them in our parades,” she said.

Hicks’s van was sixth from the end of the 49-vehicle parade, LeFurge said. She added that city officials will review their rules governing such events in light of the accident.

“We’ve never had an incident like this,” she said. “This really is a tragedy that no one could have foreseen. But it is a tragedy we’ll be looking at and learning from.”

Rhonda Wardlaw, a spokeswoman for Mayor Josh Cohen, also said the city will reexamine its parade procedures.

“In an incredibly tragic situation like this, it automatically makes the city want to take time and review current processes in place,” she said. “We have to look back, but we also have to look forward to make sure this type of tragedy — if avoidable — doesn’t happen.”

A phone message left with iWHEELiE.com, the company that owns the float, was not returned Friday afternoon.

According to the company’s Website, the bike is a 2002 Honda CBR F4i configured to allow people to simulate doing a wheelie or other tricks. Participants get about three minutes on the bike, whose rear wheel is secured to the trailer. It can be rented for parties and events for $600 for two hours.

The company posted pictures on its Facebook page from the Severna Park parade earlier in the day. The photos show the bike raised up at an angle with the front wheel in the air. Different people were pictured atop the bike.

The Facebook page also included a photo showing several adults and a couple of children on the trailer with the caption, “Ready for round 2!”