Mumbai: The mail arrived at 10.12am, and by noon the city had been swept.
It named the mayor's office at the BMC headquarters, a bank, a court, actor Amitabh Bachchan's Jalsa bungalow, Mahalaxmi Racecourse and Chhatrapati Shivaji Maharaj International Airport.
The message carried the words "Khalistan bolega, Mumbai zindabad", and referred to a car bomb attack on the Jalsa bungalow and an iPhone bomb at singer Diljit Dosanjh's Mumbai concert, officials said.
The mail named the municipal corporation directly, so the Bomb Detection and Disposal Squad moved into the BMC headquarters. The mayor's office was checked with particular care, and the building was swept with multiple devices. "Nothing suspicious was found during the search," police said. The airport and racecourse premises were also checked.
A short while later, Pune Municipal Corporation received its own bomb threat email. The city's bomb detection and disposal squad reached the civic headquarters, carried out a thorough sweep, and found nothing suspicious either.
This is the third such mail in a little over two weeks. On 23 October, the mayor's office received a threat that also named Bachchan's Juhu home and the 27 November concert at Mahalaxmi Racecourse. An outfit calling itself the Khalistan National Army claimed responsibility, and Manish Kalwaniya, deputy commissioner of police for Zone 1, said checks had found nothing suspicious.
A similar mail on 6 November was marked to the Bombay High Court and warned of attacks on the Bombay Stock Exchange, the racecourse and the concert venue. Police deployed additional personnel around the high court, other court premises and sensitive public places.
The Maharashtra Cyber Cell and local police are tracing the origin of Thursday's message, the server and account it came from, and any link to the earlier threats.
Such threats have arrived before, and most turn out to be hoaxes. Agencies still treat each one as real, because the cost of being wrong is high.
Next: what the cyber cell's trace shows, and whether security at the concert venue changes before 27 November.