Sunday Adeyemo, Yoruba nation agitator popularly known as Sunday Igboho, and his wife are being interrogated by Beninese security operatives.
According to Beninese website, RFI, the separatist activist and his wife have been undergoing questioning since Wednesday.
Igboho was meant to be arraigned in court on Thursday but he is yet to show up.
His supporters had earlier converged at the court but later moved to the Brigade Criminelle facility where he is being held.
Igboho and his wife were arrested at Cardinal Bernardin International Airport, Cotonou, while on their way to Germany on Monday night.
He was declared wanted by the Department of State Services (DSS) earlier in July after a raid on his Ibadan house.
Two people were killed by the DSS in the late night raid while 12 other persons were arrested and later paraded in Abuja. They have since been charged to court.
On Wednesday that some Yoruba living in and around Cotonou thronged the court awaiting the commencement of the trial.
There are no clear reasons why the proceedings did not commence yesterday. Ropo, Igboho’s wife who was arrested with him at the airport, is a German citizen.
Igboho had filed for political asylum in Germany before his arrest.