K. Rajendra Kumar, director general prisons, told reporters here that the body of Showkat Ali, son of Barkat Ali, a resident of Pind Sail Jathan in Sialkot Pakistan, was found hanging from the iron window of a barrack toilet inside the prison on Saturday morning.
"Pakistani and Bangladeshi inmates who were in the same prison informed the authorities in the morning about the incident," Kumar said.
He said a magisterial probe into the death has been ordered.
Ali was arrested in Jammu in February 2011 after he crossed over from the international border.
He was reportedly suffering from some mental ailment and was lodged in the Amphalla district jail in Jammu following court orders.
An FIR has been registered.