National Police Agency Commissioner General Yoon Hee-keun said an investigation into the death of a Marine during a post-monsoon search operation in July will start from square one amid concerns over improprieties.

Yoon made the remark during Thursday's parliamentary audit when grilled about the police sending case files from an internal Marine Corps probe to the military prosecution upon request.

In response to independent Rep. Lee Sung-man's criticism over the transfer, the police chief said the defense ministry had officially notified the police that it would take the records due to a procedural flaw soon after they were received by the police.

Yoon did not, however, directly respond to a call for the police to demand the immediate return of the records or else conduct a raid to seize them.

Col. Park Jung-hun, the former head of the Marine Corps investigation, faces accusation of disobeying a ministerial order not to hand over the initial findings to the police, which assigned criminal liability to eight people, including Lim Seong-geun, the commander of the Marine Corps' First Division.