Police said Dharmindra Yadav (20) was abducted by the husband of his sister-in-law Naresh Pal alias Bunty and two accomplices from his Wazidpur residence on September 29.
They later strangled Dharmindra to death in Bulandshahar and threw the body in a canal, the arrested said during interrogation.
Police suspect that Naresh hatched the conspiracy to take possession of a property owned by Dharmindra in Chhijarsi area.
A team has been sent to retrieve the body, a police officer said.