Hyderabad, Sep 3 : A youth was killed and his sister was injured in an attack by another youth over an alleged love affair in Hyderabad on Sunday, police said. The assailant barged into a house in RTC Colony in LB Nagar and attacked the youth, Prithvi, and his sister, Sanghavi, with a knife. The duo were admitted to a nearby hospital, where Prithvi later succumbed to his injuries. Police have arrested the attacker, identified as Shivakumar. He was allegedly pressurising Sanghavi for the marriage. Deputy Commissioner of Police Sai Sri, who visited the crime scene, said the police were questioning the accused. She said the murder was linked to a love affair but further questioning of the accused would help police to find out more about the motive behind the murder. Sanghavi is a homeopathy practitioner while her brother was an engineering student. They hailed from a village in neighbouring Rangareddy district. Police have registered a case and took up investigation. A police team gathered clues from the crime scene. /IANS