Rancho Cucamonga, CA- A four year old girl was killed in the Los Angeles-area when she was thrown from a motorcycle and run over by a semi Tuesday morning.

Breann Creer was riding on the back of her mother’s boyfriend’s motorcycle on 6th Ave. The pair was traveling eastbound when a semi made a U-turn. The motorcycle driver, Eric Henderson, had to force the bike on its side and became trapped underneath the big rig, Los Angeles CBS reported.

The semi ran over Breann and dragged her several feet before coming to a stop.

Cheri Slocumb, who worked in the area and heard the crash from her desk, told KABC-TV that the semi driver kept going until she and others flagged them down to told them to stop.

Slocumb also said that when she went to the girl, she was not breathing. Breann was pronounced dead at the scene.

Henderson suffered moderate injuries and was taken to a local hospital.

Investigators are still trying to determine the exact cause of the accident, but told KABC-TV that the semi was not making an illegal U-Turn.

“At this point, from what I can tell on the street, it doesn’t appear to be any type of illegal maneuver. However, the major accident investigation team is going to determine the exact cause,” Cpl. Randy Naquin with the San Bernardino County Sheriff’s Department told ABC.

Breann’s father, isn’t angry with Henderson, but says he believes the truck driver was negligent. Henderson also places the blame on the truck driver.

But investigators are reluctant to place any blame until they conclude their investigation.

According to state law, children can ride on motorcycles so long as they are wearing a helmet, and are tall enough to reach the passenger pedals. Police have not yet determined if he will face charges.

A business owner on 6th Street told NBC Los Angeles that making a U-turn on the busy street is dangerous.

“It someone pulls a U-turn on in front of you, if you they don’t see you, and (you’re) just feet from it, you can’t stop. You can’t,” Don Watson said. “And you have to ride like you’re invisible, because you are. People don’t see you. They just don’t see you.”

Reports indicate that there were two drivers in the truck, so some wonder why they were unaware of the motorcycle.

This is a heartbreaking story, and, while motorcycle enthusiasts will defend the right to allow their toddler to ride on their bikes, this accident should give them cause to consider whether that is a wise move.

While it is difficult to assign blame to either Henderson or the truck driver at this moment, if the truck driver is ultimately found liable, Breann’s family can pursue the driver for a wrongful death claim. That is probably the furthest thing from their minds, but sometimes it is the only way a family can get a sense of justice for their lost loved one.