Thiruvananthapuram | A bomb threat to the Kerala State Secretariat, which put police personnel in a tizzy, turned out to be a hoax here on Thursday.

Police confirmed that the threat, received at their headquarters in the morning, was a prank call made by a man suspected to be mentally unsound.

"A man, identified as Nidhin, was taken into custody. He is a resident of Uchakkada in Pozhiyoor (in Thiruvananthapuram). As per our primary assumption, he is not mentally stable," a senior police officer told PTI.

The Secretariat is the administrative complex that houses the offices of Chief Minister Pinarayi Vijayan and other ministers.

As soon as the bomb threat was received, police personnel, aided by sniffer dogs, conducted thorough searches both inside and outside the Secretariat premises.

Even parked vehicles and nearby shops were not exempted from scrutiny.