Investigation drags onThe investigation into alleged missing helicopter parts began 15 months ago with the internal affairs division of the Public Safety Department. Its findings were forwarded to Oklahoma County District Attorney David Prater, who gave it to state Attorney General Drew Edmonson, citing Edmonson’s better resources to investigate a case spanning multiple counties. The attorney general’s office in August asked the state auditor for an investigative review. It will be at least a month before it’s released to Edmondson, said Trey Davis, spokesman for the auditor’s office. Davis said their investigation included the inspection of parts records from Troop O and surveillance tapes. Marcus Dunn, owner of Specialty Aviation Services in Seminole, said an FBI agent and a member of the trooper’s internal affairs division questioned him in June about helicopter parts that were unaccounted for. Dunn said they repeatedly told him he had done nothing wrong, but were looking to corroborate information given to them by members of Troop O. Dunn said for at least five years, he inspected military surplus helicopter parts for the patrol. Part of his job included determining whether the parts were worthy enough for an 8130-3 tag — an approved parts return to service tag. The tag makes the parts more valuable to trade for other parts or services, Dunn said. Dunn said he showed the investigators all of the parts he was holding for Troop O and an inventory list that showed each was accounted for. He said they couldn’t have been too concerned about the parts, because it was six months before anyone with the patrol retrieved them.