Yoon said Wednesday he had agreed to leave his compound to avoid “bloodshed”, but that he did not accept the legality of the investigation.
His supporters have gathered in front of the court since Friday, holding South Korean and American flags and demanding judges dismiss the request to extend the president’s detention.
The court closed its entrance on Friday evening to the public, citing safety concerns.
Yoon has refused to answer investigators’ questions, with his legal team saying the president explained his position when detained on Wednesday.
The president has also been absent from a parallel probe at the Constitutional Court, which is mulling whether to uphold his impeachment.
If the court rules against Yoon, he will lose the presidency and elections will be called within 60 days.
He did not attend the first two hearings this week, but the trial, which could last months, will continue in his absence.
Although Yoon won the presidential election in 2022, the opposition Democratic Party has a majority in parliament after winning legislative polls last year.
The Democratic Party has celebrated the president’s arrest, with a top official calling it “the first step” to restoring constitutional and legal order.
As challenges against the embattled leader mount, parliament passed a bill late Friday to launch a special counsel probe into Yoon over his failed martial law bid.
Source: CNA
