The caller who made threatening calls to the Nagpur office of Union minister Nitin Gadkari and demanded Rs 100 crore is an inmate of a jail in Belagavi city of Karnataka who was sentenced to death by a court in a murder case in the past, police said on Sunday.

The caller, who had claimed he was a member of the Dawood Ibrahim gang, has been identified as Jayesh Pujari. Prime facie, he made the call using a mobile phone from the jail, a senior officer said.