Identified as Shanawaz Hussain, who used to work as a journalist earlier, was detained from his house from Mango police station area following inputs provided by the intelligence department, they said.
A police team seized a computer from his house, the sources said, adding that all the saved threat SMSes have been deleted from the computer.
Additional Superintendent of Police Rajiv Ranjan confirmed that a person was detained and later set free following interrogation.
Ranjan refused to divulge further details.