A woman who does not want to be identified says her children were among the victims. She claims her kids suffered injuries from either being hit by debris or being thrown to the ground.
The Rancho Cucamonga Police Department held its annual open house with the bounce house on April 30.
During the event, a sheriff's helicopter landed on the rooftop helipad when the downdraft from it caused the bounce house to lift off the ground, officials say.
Three children were taken to the hospital for treatment. Officials say one child who was inside the bounce house at the time of the incident did not need to go to the hospital.
The children's parent says she was given no warning about the helicopter.
The sheriff's department says it was publicized that the helicopter was part of the event.
The San Bernardino County Sheriff's Department and the FAA are investigating the incident.