The victim has been identified as Suraj, a native of West Bengal, who worked as a driver for a transport firm.
He had joined some friends for drinks last evening after celebrating Holi but got involved in a heated argument with some of them.
In no time, a scuffle ensued and Suraj was thrashed until he became unconscious. He was thereafter thrown into a canal in the Alipur area by his assailants, police said.
But DCP (Outer) Vikramjit Singh said police will wait for the post-mortem report to ascertain whether he had died because of physical assault or due to drowning.
"We have registered a case of murder and have arrested two persons, both of whom were friends of the victim. We suspect the involvement of two more persons," he said.