CAIRO - Former Egyptian President Hosni Mubarak appeared in court on Wednesday for the fourth time along with his two sons and former Interior Minister Habib el-Adli.

Former Egyptian president Hosni Mubarak lies on his bed while being taken to the courtroom at the police academy in Cairo September 7, 2011. An Egyptian court trying Mubarak over the killing of protesters who ousted him convened on Wednesday to hear more testimonies after police witnesses suggested this week that neither he nor his interior minister gave orders to shoot. [Photo/Agencies]

The three witnesses who will testify in the trial are Security Forces Sheriff Mohamed Abdel-Hakim, Security Forces Sheriff Sergeant Abdel-Hameed Abou Yazeed, and former police officer Tarek Abdel-Menem who took part in the demonstrations and injured by bullets in his legs.

The trial started at 10:30 am (0830 GMT) amid disorder in the court, which led some civil plaintiffs leaving the trial. Clashes erupted outside the court among families of the killed in the Jan. 25 protest and policemen.