A Dera Sacha Sauda follower, arrested in connection with the violence in Panchkula on August 25, allegedly hung himself in the toilet of the Ambala Central Jail, the police said.
The deceased was identified as Ravinder (28), a resident of Sarsawa in Uttar Pradesh.
The Dera follower was arrested on August 25 in Panchkula where violence broke out after the conviction of the sect's chief Gurmeet Ram Rahim Singh in rape cases, Ambala's Superintendent of Police, Abhishek Jorwal said.
Ram Rahim was later sentenced to 20 years in prison by the special CBI court.
After his arrest, Ravinder was lodged in the Ambala jail on judicial remand.
An inmate found him hanging in the jail's toilet and informed the authorities. His body was shifted to the local civil hospital for post mortem examination.
Jorwal said deceased's relatives had been informed.
Meanwhile, jail authorities have ordered a probe into the incident.
The security of Dera followers, who were arrested in connection with the violence in Panchkula on August 25 and lodged in the jail, has been tightened, jail sources said.