Nitin Gupta (22) was allegedly stabbed by Rahul in Mithilapuri Colony last night, Additional Superintendent of Police Rajiv Malhotra said.
Gupta was rushed to a private hospital by his friend Tarun, but doctors declared him dead, he said.
The ASP said Gupta had booked a room on rent for Tarun in Rahul's house for which he had paid Rs 1,000 as advance.
But later Rahul refused to rent the room to Tarun, he said.
Gupta went to Rahul's house last night to take his advance back, but the latter was not present there. Gupta then misbehaved with the women of the family, Malhotra said.
A case has been registered and efforts are being made to arrest Rahul, who is absconding.