HYDERABAD: A Task Force constable, who noticed an incident of robbery in the early hours of Friday in the Ramgopalpet police limits, chased for at least one kilometer and nabbed three persons, including a minor boy. According to police, Y Timmappa, who works as a room boy at a hotel, was riding through Necklace road when the accused caught hold of him, took his bike and assaulted him. Later, the accused robbed `400 and a mobile phone from the victim. Constable Vidya Sagar who was on duty happened to hear Timmappa’s screams for help. Subsequently, the constable chased the accused for one kilometer and nabbed them. The accused were handed over to Ramgopalpet police.