This photo shows former Defense Minister Kim Yong-hyun, Dec. 3. Yonhap

Prosecutors questioned former Defense Minister Kim Yong-hyun on Sunday as part of an investigation into alleged treason following President Yoon Suk Yeol's short-lived martial law imposition last week.

Kim was a central figure in Yoon's abrupt martial law declaration late Tuesday that lasted six hours before being withdrawn due to a National Assembly vote against it.

Some have suggested that Kim was the one who advised Yoon to declare martial law.

Kim, who resigned shortly after the lifting of martial law, voluntarily appeared at the Seoul Central Prosecutors' Office early Sunday, where he was taken into custody at a detention facility in eastern Seoul under emergency arrest provisions.

Under an emergency arrest, the prosecution has 48 hours to detain and question the suspect.

Prosecutors questioned Kim for about six hours as soon as the arrest was made. About nine hours later, they quizzed Kim for a second time until about 10 p.m., officials said.

The prosecution questioned Kim over his involvement in the process of implementing the martial law, such as what orders he had received from Yoon and what instructions he gave to the martial law command.

Kim was apparently active in explaining his position and hardly refused to answer, according to officials.

He admitted that he suggested to Yoon declaring martial law and maintained that nothing in the process was illegal or unconstitutional.

Prosecutors are believed to have arrested Kim considering the gravity of his charges and concerns over the possibility of the former defense chief destroying evidence.

Speculation that Kim may attempt to destroy evidence rose after he was found to have joined Telegram again after deleting his previous account.

The prosecution is expected to restore previous conversations he had on the messaging platform.

By law, suspects can be arrested without a warrant if there are considerable grounds for believing a serious crime has been committed or when there are concerns over a possible attempt to destroy evidence.

The prosecution is expected to file for a court warrant to formally arrest Kim as early as late Monday. If prosecutors fail to apply for a warrant or the court rejects it, Kim will be released immediately. (Yonhap)