Chandrashaker Patidar hanged himself from an iron angle inside the lock up of the department office yesterday, Circle In charge of Kota Narcotic Department, Dharm Singh Meena, said.
A judicial as well as departmental inquiry into the case has been ordered, he said.
The smuggler was arrested on September 20 and was under custody by court's order.
He was arrested from his rented home in Mandsour district in Madhya Pradesh and drugs worth around Rs 5 crore were recovered from his possession, Meena said.
A case under Section 176 of CrPC was lodged in this connection and a judicial probe is underway, SHO of Jawaharnagar police station, Harish Bharti, said.