Describing the sequence of events, a police official said, Ashwani entered the house of one Brijbir in Khatoli area on March 15 with a motive to rob him but was caught red-handed.
Brijbir and five others thrashed him brutally and later handed him over to police.
Ashwani was sent to judicial custody, he said, adding, he was shifted to a hospital after his health deteriorated.
He succumbed to his injuries on March 19, he said.
On the complaint of Ashwani's mother, Ramlesh, a case was registered against Brijbir, Poonam, Ashok, Anil, Amit, Tavinder under relevant sections of the IPC for allegedly thrashing her son to death, police said.