The interrogation follows the recent dissolution of Bashir's National Congress Party (NCP) and confiscation of the party's funds by the new Sudanese government.
Earlier, the prosecutor general's office decided to detain all military personnel who participated in the coup 30 years ago, and a special commission was established to investigate the case.
Bashir is also a defendant in a corruption case, the hearings of which began in August. He is charged, among others, with illegally obtaining funds from the leadership of Saudi Arabia and using them for personal purposes. Bashir, however, rejects these allegations.
The court decision on the corruption case is expected to be announced on Saturday.
In addition, the former Sudanese president is a defendant in an international investigation.
In 2009, he became the first acting head of state in history to be subjected to an arrest warrant issued by the International Criminal Court in connection with charges of genocide and crimes against humanity committed during the 2003 conflict in Darfur.
Bashir governed Sudan for about 30 years before he was overthrown by a military coup in April, which brought the Transitional Military Council (TMC) to power after months of anti-government protests.
However, the demonstrations continued with opposition protesters calling on the TMC to transfer power to a civilian-led government. The TMC and the opposition subsequently concluded a power-sharing agreement, establishing the Sovereign Council.