The fifth grader was at the festival with her family. She was on a ride identified in court documents as the Super Sizzler.
Attorneys for the family allege the ride was not stopped immediately after the girl was thrown off it, resulting in further injury. McMullen died later that day at Cooper University Hospital in Camden.
A state police spokesman on Friday said the accident investigation is active.
Parents Amanda and Christopher McMullen have hired two law firms. Their attorneys have stated they are exploring wrongful death, survival action, and emotional distress lawsuits.
Cherry Hill attorney Louis DeVoto filed a request in December 2020 with the Middlesex County Superior Court for access to all state police reports. The state Attorney General s Office said the file is not considered a public record and a court order would be needed to release it, DeVoto told the court.