( CNN ) -- Egypt 's general prosecutor on Monday extended the detention of two of former President Hosni Mubarak 's sons , saying further investigation is needed . Gamal and Alaa Mubarak will be held for another 15 days , the prosecutor 's office said in a statement , adding that members of the office went to Tora prison to conduct questioning . Gamal and Alaa Mubarak 's lawyers were present , the statement said . The two were being questioned `` regarding the prices of their real estate , lands and their role in intervening in the program of settling Egypt 's debts , '' as well as commissions on a gas deal with Israel and their roles in `` mandatory partnerships with foreign companies in Egypt , '' the statement said . They were also being asked about `` their role in privatization and evaluation of private shares and selling them , '' the prosecutor 's office said . Last month , Egyptians exulted over the detention of their ailing former president and his two sons in a probe exploring the killing of protesters in Cairo 's Tahrir Square , the center of the country 's dramatic uprising earlier this year that led to Mubarak 's ouster . Mubarak and his two sons were detained in connection with the protesters ' deaths , an official with Egypt 's Justice Ministry said at the time . Prosecutors have also been investigating what properties and bank accounts the Mubaraks have . Hosni Mubarak has decried accusations of responsibility in the deaths , saying the probe is aimed at tarnishing his reputation and that of his family . He has also said he and his children have not violated any laws , and that an investigation of the properties they own will show they 've done nothing wrong .
Gamal , Alaa Mubarak were detained in April . Prosecutor says they 're being questioned on real estate , other financial deals . Hosni Mubarak has denied wrongdoing by him or his sons .