Esam el-Erian, vice chairman of the Freedom And Justice party, said on Twitter that Hamada Saber, who was dragged, stripped naked and beaten up in front of the Ettehadiya Presidential Palace, belongs to Muslim Brotherhood, and was demonstrating there to support president Mohammed Morsy.
It's worth mentioning that Hamada has told the prosecution that police haven't assaulted him, but rather were trying to protect him. However, his family assures that he was threatened by policemen, and he is lying.