The Corruption Investigation Office for High-ranking Officials (CIO) concluded its search of the National Security Office and the Presidential Secretary's Office on the 8th regarding the allegations of pressure in the investigation of the Marine Corps death case. The CIO attempted to conduct a search the day before, but it failed due to the lack of cooperation from officials. However, it stated that the search was "smoothly conducted" on that day.
On that day, the CIO announced in a notice sent to reporters that the search of the Presidential Secretary's Office and the National Security Office, carried out by the CIO investigation team at around 10:30 a.m., concluded at about 4:30 p.m. It added that the operation was conducted smoothly with the cooperation of the relevant institutions.
The CIO attempted to conduct a search of the National Security Office and the Presidential Secretary's Office the day before, but it failed. This was because the Secretary to the President and the Head of the National Security Office did not grant final execution permission. Consequently, after starting the search, the CIO halted operations and withdrew about 6 hours and 30 minutes later. As a result, the search was re-attempted and successfully carried out on that day.
Meanwhile, the allegations of pressure in the investigation of the Marine Corps death case are related to the death of Corporal Chae Soo-keun, who was swept away by rapids while participating in the search for missing persons due to flooding in Yecheon County, North Gyeongsang Province, in July 2023. Allegations have emerged that officials from the Presidential Office and the Ministry of National Defense exerted pressure during the process in which the Marine Corps investigation unit, which investigated the case, designated former Commander Lim Seong-geun and others as responsible for Corporal Chae's death and referred the case to the police.
Park Jeong-hoon, the former head of the Marine Corps investigation unit (Colonel), who led the initial investigation, reportedly received an instruction from superiors to withhold the transfer of investigation materials to the police but did not comply. He later revealed that he heard that President Yoon Suk-yeol was furious after being briefed on the investigation unit's findings, exacerbating the allegations.