Johannesburg - A serial rapist picked out of a police line-up through his voice, was on Thursday convicted on 53 charges, including rape and robbery with aggravating circumstances.Known as the "balaclava rapist", Sinja Robin Mabitsela, of Alexandra, used a scarf and red towel to hide his face when he appeared in the High Court in Johannesburg.The 38-year-old entered into a plea agreement on Wednesday. Judge Carla van Veenendaal convicted him on multiple counts of rape, compelled rape, assault, sexual assault, and robbery with aggravating circumstances.Mabitsela, who wore a balaclava during his attacks, started raping his victims in 2007. He was arrested in 2015. His victims were aged between 13 and 38.According to Women and Men Against Child Abuse (WMACA), Mabitsela and his co-accused were arrested after DNA evidence linked them to a series of rapes with the same modus operandi.The anti-abuse group said Mabitsela had targeted couples and girls in and around the Alexandra park region and the East Bank cemetery.His alleged accomplice, Xaniseka Mukansi, pleaded not guilty. Mukansi is expected back in court on March 24.Speaking to reporters outside the court, WMACA’s kids clinic manager, Elizabeth Mokoena, said she has been providing the victims with support and counselling."After he [Mabitsela] was arrested, the victims identified him by his voice during an ID parade. They were very traumatised when they approached the police and the clinic," Mokoena said. The matter was postponed to March 30 to determine the progress made on getting victim impact statements, and to set a date for pre-sentencing hearings.