AUBURN — A county prosecutor said Monday that a criminal investigation into an Oct. 11 haunted hayride in Mechanic Falls that turned deadly is ongoing and won’t be concluded until the report of a hired expert is complete.

In a prepared statement, Androscoggin County District Attorney Andrew Robinson said his office has reviewed hundreds of pages of investigative reports.

“It became very clear that we needed the opinion of an expert to address the question of exactly what contributed to the crash,” he said. “We have secured the services of a prominent expert who is very skilled in dealing with these types of cases, and we are awaiting his final report.”

Once Robinson’s office has that report, he said the “appropriate decisions” will be made regarding criminal prosecution.

On the night of Oct. 11, a flatbed hay wagon laden with dozens of spectators spilled its riders into the woods when the flatbed rolled over after the Jeep that was pulling it down a steep hill jackknifed and slammed into a tree. By the following morning, it was revealed that a 17-year-old girl from Oakland had died and nearly two dozen others were badly hurt, suffering broken bones and head, back and neck injuries.

The ride took place at a Halloween attraction called the Gauntlet at Harvest Hill Farms on Route 26. Investigators said it appeared a mechanical failure led to the rollover, in which Cassidy Charette, a student at Messalonskee High School, died of her injuries. Also seriously hurt was Charette’s boyfriend, 16-year-old Connor Garland of Belgrade.

Teams of investigators from state agencies spent weeks probing the cause of the wreck. The district attorney had planned to present findings to a grand jury in February, but that office has stretched the length of that time frame months longer.

“I consider this case to be very important and will take every step necessary to ensure that it is handled properly,” Robinson said. “I am also aware that the public is interested in knowing the status of the case and has a right to know. However, this remains an open investigation, and we are prohibited from discussing details of the case further until a final decision has been made.”

The Office of the State Fire Marshal completed its report from its investigation last fall.

Troopers, motor vehicle inspectors and state fire investigators inspected the 1979 CJ-5 at a local garage, the result of a search warrant. The vehicle autopsy was aimed at detecting any mechanical failure that might have occurred on the night of the crash. Towing capacity of the Jeep also was a focus of the investigation.

The results of the Jeep inspection were included in a final investigative report that was provided to the Androscoggin County District Attorney’s Office.

cwilliams@sunjournal.com