Oh Dong-woon, the nominee for the head of the Corruption Investigation Office for High-ranking Officials (CIO), attends his confirmation hearing at the National Assembly in Seoul, May 17. Yonhap

The nominee for chief of the anti-corruption investigation body pledged a thorough probe Friday into an alleged interference case related to the death of a young Marine, saying President Yoon Suk Yeol could, in principle, be subject to a summons.

Oh Dong-woon, a former Seoul High Court judge nominated to head the Corruption Investigation Office for High-ranking Officials (CIO), made the remarks at a parliamentary confirmation hearing, saying he will investigate the case thoroughly according to the law and principles "without the slightest" mistake.

The CIO has been investigating allegations that Yoon's office and the defense ministry inappropriately interfered in a military investigation into the death of Cpl. Chae Su-geun during a search mission for downpour victims in July 2023.

Oh said that for a president, there are regulations for exceptions from criminal prosecution unlike for the general public, but Yoon can "indeed be a subject of investigation."

During the hearing, lawmakers of the main opposition Democratic Party of Korea (DPK) renewed calls for a special counsel probe into Chae's death, pointing to mounting suspicions about the presidential office's possible involvement.

Meanwhile, the ruling People Power Party defended the CIO's ongoing investigation into the Marine's death as "proceeding well compared to other cases."

"Asserting that a special counsel probe is needed is akin to arguing that the CIO investigation is lacking, and that the agency is unable or unwilling to investigate properly," Rep. Jang Dong-Hyeok said.

During the one-day hearing, Oh also said he will aim to "protect the prosecutors at CIO from external pressure so they can perform their duties solely based on the law and principles."

"We will put our utmost efforts to protect the political neutrality and independence of the CIO and to eradicate corruption among high-ranking officials in strict accordance with the law and principles and ensure transparency and public trust in government officials," he said.

Oh's confirmation hearing comes four months after the inaugural CIO chief, Kim Jin-wook, retired following a three-year term. The CIO was created in 2021 to uproot corruption among high-ranking officials.

Oh served as a judge from 2002-2017.

Oh's confirmation hearing is widely seen as a formality because his formal appointment does not require the endorsement of the National Assembly.

In Korea, the prime minister is the only Cabinet post that requires parliamentary approval. (Yonhap)