A police team took him to the police station from his residence last night and formally arrested him, official sources said.
He was produced today in the court of the Chief Judicial Magistrate R N Tripathy who remanded him to judicial custody for 14 days.
An FIR had been lodged against Agarwal under section 302 of IPC by Neeraj a reporter of a Hindi daily and brother of the deceased, Dheeraj Mahato.
Agrawal has claimed that Dheeraj was killed on July 17 when the carbine of his bodyguard accidentally went off.