SEOUL: South Korea's suspended President Yoon Suk Yeol refused summons to appear for questioning on Sunday, the third time he has defied investigators' demands in two weeks.
Investigators probing Yoon had ordered him to appear for questioning at 10 am (GMT 0100) on Sunday, a demand he rejected.
Yoon, a former prosecutor, also failed to attend a hearing he was summoned to last Wednesday, giving no explanation for his absence.
The conservative leader was stripped of his duties by parliament on December 14, following a short-lived martial law declaration that plunged the country into its worst political crisis in decades.
Yoon faces impeachment and criminal charges of insurrection, which could result in life imprisonment or even the death penalty, in a drama that has shocked democratic South Korea's allies around the world.
"President Yoon Suk Yeol did not appear at the Corruption Investigation Office for High-ranking Officials (CIO) at 10 am today," said the office in a statement.
"The Joint Investigation Headquarters will review and decide on future measures," it added.
The CIO is expected to decide in the coming days whether to issue a fourth summons or ask a court to grant an arrest warrant to compel Yoon to appear for questioning.
He is being investigated by prosecutors as well as a joint team comprising police, defence ministry, and anti-corruption officials, while the Constitutional Court deliberates on the impeachment motion passed by parliament.
If upheld by the court, which is required to deliver its ruling within six months of the impeachment, a by-election must be held within 60 days of the court's decision.
Former president Park Geun-hye was impeached under similar circumstances, but she was investigated only after the Constitutional Court removed her from power.
A 10-page prosecutors' report seen by AFP stated that Yoon Suk Yeol authorised the military to fire their weapons if needed to enter parliament during his failed bid to impose martial law.