The arrest of three men accused of sexually assaulting a four-year-old girl underlines the need for Dubai Police's new child protection unit, a senior officer said...A bus driver, a cleaner and an attendant at a private school in Dubai were arrested last week after the four-year-old girl was sexually assaulted on her school bus...Many cases of child sex abuse go unreported because families are not willing to talk about such crimes in public, experts say...The managing director of the bus company said: "We were planning to install cameras in all our buses, and in light of this incident we think it is necessary to look at these measures immediately." He also said that all available evidence had been handed over to police. The case has been referred to public prosecutors.