Kerala police launched a probe after a District Collector in Rajasthan received a hoax email claiming that explosions would take place at collectorates and courts across Kerala.
Thiruvananthapuram City Cyber Police registered a case on Friday and began an investigation into the incident, police said on Saturday.
According to police, the email was received on May 6 in the official email ID of the District Collector of Bikaner in Rajasthan.
Police said the email, written in Hindi, claimed that explosions would occur at courts and collectorates across Kerala.
The Rajasthan Police subsequently alerted Kerala Police, following which security checks were conducted at various locations in the state.
The threat was later confirmed to be a hoax, police said.
Based on directions from the Police Headquarters, the Cyber Police registered a case and launched an investigation to identify the person behind the email.
Police officials said the email was suspected to have been generated using a dark web platform and further investigation was underway.
The case has been registered under various sections of the Bharatiya Nyaya Sanhita, the Information Technology Act and the Kerala Police Act, police added.
(With inputs from PTI)