Bikaner:�A physical trainer and instructor has been arrested for allegedly raping and killing a Dalit girl in the hostel of their college in Bikaner district. The body of the 17-year old girl was found in a water tank on Tuesday morning following which her parents lodged a complaint against trainer Vijendra Singh accusing him of raping and killing the girl, police said. The accused was arrested on Wednesday and under police custody, the police said. "It was alleged that the girl was raped in the hostel room of Vijendra on Monday night and later her body was found in the tank. She was pursuing BSTC (a course to become teacher) from the private college in Nokha," the police said. The Dalit girl belonged to Barmer district. Local people, her relatives and public representatives including Leader of Opposition Rameshwar Dudi have demanded a probe into the matter.