Presidential chief of staff Chung Jin-suk, right, listens to lawmakers' questions during a meeting of the National Assembly House Steering Committee in Seoul, Monday. On left is First Deputy Director of National Security Kim Tae-hyo. Yonhap

Lawmakers of the main opposition Democratic Party of Korea (DPK) slammed aides to President Yoon Suk Yeol over suspicions that his office had influenced the military's investigation into the death of Marine Cpl. Chae Su-geun last year, during a National Assembly's House Steering Committee meeting, Monday.

The meeting, the first for the steering committee in the DPK-controlled 22nd Assembly, garnered attention as it marked the inaugural instance of new DPK lawmakers questioning presidential aides, including presidential chief of staff Chung Jin-suk and other senior secretaries.

During the meeting, DPK lawmakers zeroed in on suspicions that Yoon ordered the military to scale down its investigation into the death. Chae died on July 19 during a search and rescue operation after floods. The main opposition party has insisted that related suspicions should be addressed through a special counsel probe. Yoon rejected a bill to launch the probe by using his presidential veto power.

Lawmakers and secretaries of President Yoon Suk Yeol attend a National Assembly House Steering Committee meeting in Seoul, Monday. Yonhap

DPK Reps. Choo Mi-ae, Ko Min-jung, Noh Jong-myun and Kwak Sang-eon questioned whether Yoon said, "Marine commanders should not be punished for such an incident," during a meeting with his senior secretaries at 11 a.m. on July 31, 2023, and then ordered the Marine's investigation team to retrieve its investigation reports previously handed over to police.

"There are reports that Yoon flew into a rage during the July 31 meeting saying ‘who will serve as (Marine's) commander if one gets punished for such an incident' and ordered his staff to call then-Defense Minister Lee Jong-sup. Phone records show Lee received a call at 11:54 a.m., from the number 02-800-7070, which appears to be one of the phone numbers of the presidential office," Choo said.

"We need to confirm whether this number was used by the presidential office, because confirming whether the president outrageously made those remarks is the first step toward addressing the whole suspicions."

Reps. Ko, Kwak and Noh grilled the chief of staff, First Deputy Director of National Security Kim Tae-hyo and other presidential secretaries to confirm whether the phone number was used by the presidential office and whether the president actually made those remarks.

Ko raised allegations that the phone lines of the presidential office was reorganized later, and said,"If confirmed, it will be equivalent to the destruction of evidence."

Noh also described other phone records pointing to presidential aides and government officials during the period, but the chief of staff said, "It is very natural for the two sides to communicate when national security matters are pending."

Despite the DPK's suspicions, Chung and other presidential aides denied the president made such comments during that meeting, and refused to confirm the number citing national security concerns. The deputy first director of national security, who was present at the July 31 meeting, said he does not recall any occasion of Yoon getting angry about the case.

"If a bill appears to be unconstitutional, it is the president's obligation and responsibility to veto it," Chung said referring to the special counsel probe bill. "A special counsel probe should be launched through agreements between the main rival parties, and this bill, which would only allow the opposition to recommend the special counsel, goes against the principle of separating powers."

Chung reiterated Yoon's earlier remarks that the special counsel probe should come only after related investigations are deemed insufficient, and added, "If the special counsel probe is launched, the authorities investigating this case have to hand over their investigative rights to the special counsel probe."

Former Marine investigation team head Col. Park Jung-hoon, left, speaks during a National Assembly hearing on the 2022 death of Marine Cpl. Chae Su-geun in Seoul, June 21. While Park claimed the investigation was influenced by the Yoon Suk Yeol administration, then-Defense Minister Lee Jong-sup, right, and Lim Seong-geun, former commander of the 1st Division of the Marine Corps, refused to be sworn in as witness. Yonhap

Yoon returned the special counsel probe bill to the Assembly for a re-vote on May 21. A presidential veto can be overridden with the approval of two-thirds of lawmakers, but the bill was scrapped as the DPK failed to secure enough approvals before the previous 21st Assembly ended on May 29.

The DPK has tabled a similar special counsel probe bill at the current 22nd Assembly which opened on May 30 and plans to pass it during a plenary session this week. The DPK now holds 175 out of 300 seats in the Assembly, allowing the party to unilaterally pass the bill.

If Yoon returns the bill to the Assembly again, it would require the approval of 200 lawmakers in a re-vote to override his veto. Since the ruling People Power Party (PPP) holds 108 seats and minor opposition parties are endorsing the special counsel probe, approvals from only eight PPP lawmakers would virtually strip Yoon of his veto power.

Meanwhile, the chief of staff said during the meeting that the Yoon administration will create a new ministerial post for political affairs to improve communication with the Assembly.