The accused Ismail Uddin, his father Azard Ali, mother Anuwara Begum and brother Rahim Uddin are absconding.
The incident triggered outrage among locals who demanded a high-level probe into the incident.
The deceased – 58-year-old Basudev Biswas – was lodged at the detention centre in Central Jail, Tezpur. The police said he died on Saturday evening while he was being taken to a hospital for treatment
The victim, Shaukat Ali, who was injured in the incident, was admitted to a local hospital for treatment.
An Assam man was declared a foreigner by the Foreigners’ Tribunal two years ago and sent to a detention centre as the name of his grandfather mismatched in some documents.