An anonymous bomb threat email sent to Mantralaya triggered a police search and heightened security in Mumbai. Separately, a passenger joking about a bomb during a security check at Kolkata Airport was detained, causing a brief scare. Mumbai: Mantralaya, administrative headquarters of the Maharashtra government situated in south Mumbai, received a bomb threat, the police said on Tuesday. The warning was issued via an email to the Disaster Management Control Room on Monday evening. Following which, the police and other officials went on a high alert. The email said that there would be an explosion in 48 hours in the city, but did not mention a specific place.