Oh Dong-woon, chief of the Corruption Investigation Office for High-ranking Officials, speaks to reporters as he arrives for work at the office in Gwacheon, Gyeonggi Province, Jan. 22. Yonhap

Investigators failed Wednesday at their third attempt to forcibly bring in President Yoon Suk Yeol for questioning over his botched martial law bid.

Prosecutors and investigators with the Corruption Investigation Office for High-ranking Officials (CIO) visited the Seoul Detention Center in Uiwang, south of Seoul, to question Yoon over his Dec. 3 declaration of martial law, but the president refused all forms of interrogation, including on-site.

"We plan to discuss and decide the next steps in the questioning and procedures," the CIO said in a notice to the press.

The investigators withdrew after five hours while Yoon met with his legal team.

"We told the CIO he has to prepare for tomorrow's impeachment trial hearing at the Constitutional Court and that we have already conveyed everything that needs to be said," Yun Gap-geun, one of the lawyers, said.

In a statement, the legal team denounced the CIO's repeated attempts to forcibly bring in the president as a "seriously illegal investigation."

"Forcibly bringing in a suspect who has exercised his right to remain silent violates the constitutionally guaranteed right to remain silent," it said.

A vehicle belonging to the Corruption Investigation Office for High-ranking Officials approaches the Seoul Detention Center in Uiwang, Gyeonggi Province,Jan. 22. Yonhap

Oh Dong-woon, the CIO chief, had called on Yoon earlier in the day to "respect the decision of the judiciary."

"If there are objections, they can follow the steps to appeal within the legal framework," he told reporters as he arrived for work.

The CIO has resorted to bringing Yoon in by force as the president has refused to comply with orders to appear for questioning over his failed martial law bid.

The only time he sat for questioning was immediately after his apprehension at his residence last Wednesday, but even then, he exercised his right to remain silent.

Investigators went to the detention center on Monday and Tuesday to forcibly bring him in but withdrew both times after Yoon's side refused to cooperate.

Under human rights protection regulations, investigators cannot question a suspect without his or her consent after 9 p.m.

Yoon returned to the detention center past that time on Tuesday after attending his impeachment trial at the Constitutional Court and stopping at a military hospital to get a health exam.

"It kind of turned out like a game of hide-and-seek," Oh said when asked if he was aware of Yoon's plans to visit the hospital. "(The investigators) waited at the detention center because it didn't seem right from the perspective of human rights to go looking for him at the hospital."

Oh partially acknowledged that Yoon's delayed return appeared aimed at avoiding questioning.

"It's very regrettable," he said. (Yonhap)