Tejyash (19) was stabbed to death with his throat slit using a sharp-edged weapon on Tuesday morning at his home in Multani Muhalla, they said.
According to Deputy Commissioner of Police (North West) N Gnanasambandan, the deceased elder sister Navpreet Kaur was in a relationship with the accused Varun Chauhan (27) for the past seven years. The couple wanted to get married but the girl's family, especially Tejyash, was opposed to it.
The couple then planned to eliminate Tejyash assuming that after his death, the parents would approve of their relationship, the DCP said.
"Navpreet then left for office and thereafter, Varun attacked Tejyash while he was still asleep. The victim got up and resisted the attack. A sturdy scuffle happened between them but Varun succeeded in killing Tejyash," the DCP said.
Police received a PCR call around 10:30 AM that day following which they rushed the victim to Bhagwan Mahavir Hospital where doctors declared him brought dead.