The Corruption Investigation Office for High-ranking Officials building in Gwacheon, Gyeonggi Province, is seen in this photo taken on Wednesday. Yonhap

A former military intelligence commander is facing allegations of playing a pivotal role in the botched martial law scheme, with speculations growing that the retired Army general, a civilian, drafted the plan for the emergency military rule.

Noh Sang-won, the former head of the Defense Intelligence Command, was arrested late Wednesday on suspicions that include drafting the martial law decree and coordinating action plans with then-Defense Minister Kim Yong-hyun. Noh is known to be a close confidant of Kim.

Noh Sang-won, former head of the Defense Intelligence Command / Captured from Yonhap News TV

Noh, who served as the intelligence commander during the Park Geun-hye administration, is now a civilian. He was dishonorably retired in 2018 after being sentenced to one year and six months in prison without probation by a military court for sexually assaulting a female trainee.

The Seoul Central District Court issued the warrant requested by the joint investigation team on Tuesday, citing concerns that Noh might eliminate evidence or flee. According to the investigation team, Noh waived his right to attend the court's warrant review hearing on Wednesday.

Noh is accused of conspiring with the former defense minister, a senior alumnus of the Korea Military Academy, to plan President Yoon Suk Yeol's martial law imposition on Dec. 3. The minister, who stepped down on Dec. 5, is also under arrest for treason charges.

The retired general also faces allegations of directing then-Defense Intelligence Commander Army Maj. Gen. Moon Sang-ho, a junior from the same academy, to organize a special task force aimed at seizing the servers of the National Election Commission (NEC) during the implementation of martial law. Moon was taken into custody by the anti-corruption agency on Wednesday.

During the martial law imposition, which lasted for just six hours, around 10 intelligence agents were dispatched to the NEC headquarters in Gwacheon, Gyeonggi Province. They took photos of the election watchdog's internal servers and reportedly sent them to Moon. The president later explained that the troops dispatched to the NEC were part of his efforts to investigate alleged election fraud.

According to the investigation authorities, the meeting between Noh and Moon to plot martial law allegedly took place on Dec. 1, two days before the surprise martial law declaration, at a Lotteria, a local fast-food chain, in Ansan, Gyeonggi Province.

Moon and two colonels from the Defense Intelligence Command joined the meeting. The police reportedly obtained CCTV footage showing the four men engaging in discussions while eating hamburgers.

Former Defense Intelligence Commander Maj. Gen. Moon Sang-ho speaks during a parliamentary session at the National Assembly in Seoul, Dec. 10. Yonhap

In addition, opposition lawmakers have raised speculations that Noh instructed Moon to deploy the Headquarters of Intelligence Detachment (HID) unit to arrest high-ranking officials and lawmakers. The HID is an elite special forces group tasked with assassinating North Korean leadership in the event of war. The police reportedly included these speculations in Noh's arrest warrant.

Rep. Kim Byung-joo of the main opposition Democratic Party of Korea claimed that the HID's mission was to abduct NEC officials, describing this as a "shocking revelation" that has been verified through several routes.

"The unit was ordered to capture 30 personnel by force and bring them to the B-1 bunker," Kim said during an interview with MBC radio on Thursday. The bunker, operated by the Army's Capital Defense Command, serves as a command center for South Korean forces in the event of war.

"A list of the 30 targeted individuals was provided to the 38 HID members who gathered around 9 p.m. before the martial law declaration. They were instructed to bind their wrists and ankles with cable ties, cover their faces with masks and transport them," the lawmaker added.