In December, six Muslim Brotherhood members were arrested in Cairo and charged with money laundering.
It was the first time such a charge had been brought against members of the group, which is officially banned but tolerated.
Egyptian authorities have unleashed a fresh crackdown on the movement in recent weeks, arresting around 150 Brotherhood members in the wake of a December 14 demonstration at Al-Azhar university.
Despite being officially banned, Muslim Brotherhood MPs form the largest opposition bloc in parliament after winning 88 of the 454 seats by running as independents in the 2005 legislative elections.
Egyptian human right activists last week protested against police brutality and torture after the appearance of torture videos - from inside police stations - on the internet.
One particular video showed an Egyptian man being beaten and then sodomised by police officers. The officers involved were arrested by the authorities.
Another video showed a woman murder suspect, handcuffed and suspended, writhing in pain.