A Mumbai state transport bus driver was arrested on Friday for allegedly sexually assaulting a six-year-old girl on board a luxury bus, which was returning to Mumbai from Shirdi. Crime Branch officials said the accused Sopan Ugale was a resident of Oshiwara area and was attached with Goregaon bus depot as a driver.According to police, the victim and her family had boarded a luxury bus from Shirdi on the night of May 13. The accused also boarded the same bus from Sangamner area at around 10:30pm.Police said the girl’s mother told her to sit on a vacant seat next to the accused. Around 3am, when the minor was asleep, the accused sexually abused her, a police official added. The minor shared her ordeal with her mother in the morning after she started experiencing pain in her private parts. The accused, however, had deboarded the bus by that time. The victim’s family then approached the Kurar police station and a case of sexual assault under Protection of Children from Sexual Offences (POCSO) Act was registered against the accused. Meanwhile, the crime branch began its enquiry into the case and checked the passengers’ list, an official familiar with the investigation said. “Once the accused’s seat number was confirmed, we got his details. Ugale had mentioned his mobile number while booking the ticket from an agency and so we got his number. His location and residential address were traced to Oshiwara, said police inspector Sunil Jadhav.A police team visited Ugale’s residence on Friday morning and he was brought to the police station and during interrogation, he confessed to the crime, a police official said.