Mumbai - The Police arrested one for robbing a pedestrian. 32-year-old Rajkumar Yadav, a resident of Mankhurd walking towards Sion-Trombay road was assaulted and robbed by two.They snatched his mobile,1200 Rs and fled on a bike. When Yadav screamed for help an auto-wallah chased them and succeeded in catching one. Trombay police are on the lookout for the other.