Egypt's general prosecution announced on Tuesday that it began questioning former Vice President Omar Suleiman about assaults on protesters and the wealth of former President Hosni Mubarak.
The prosecution announced on its Facebook page that details of the questioning, which began Monday, will not be declared until it is finished.
Mubarak nominated Suleiman, the head of Egypt's intelligence apparatus for 20 years, as vice president on 29 January in a bid to placate protesters who demanded the former president's resignation.
Mubarak had not previously appointed a vice president during his rule, which began after former President Anwar Sadat's assassination.
Mubarak, who is now in custody at a Sharm el-Sheikh hospital because of health problems, faces accusations of ordering the killing of protesters during the 25 January revolution.
He and his family are also charged with illegally gaining wealth.
