The Delhi Police is likely to conduct a pan-India investigation with its counterparts in other states to crack the conspiracy behind email threats sent to various installations, including schools, hospitals and airports, in other states, officials said on Monday, May 13.

According to a Delhi Police officer, the officers are analysing the pattern of the emails and planning to approach the police forces of other states.

In the last two weeks, schools and hospitals in cities like Delhi, Bengaluru, Ahmedabad, Jaipur and Lucknow, and airports in Delhi, Mumbai, Goa, Nagpur and Kolkata, besides various government buildings received the threats from foreign-based mailing service companies that have advanced data encryption.

Investigations in these cities are underway, police said.

Twenty hospitals, the Delhi airport and the Northern Railway's chief public relations officer's (CPRO) office received the emails warning about the "placing of explosive devices inside the buildings" on Sunday, May 12.

The Delhi Police carried out searches but nothing suspicious was found.

The officer said Sunday's threat was sent from Europe-based mailing service company beeble.com.

Police will soon write to Interpol to get information about the IP (internet protocol) address of the device from which the email was sent, he added.

The Special Cell of the Delhi Police is conducting the investigation, he said.

The officer further said the sender had used a similar domain service provider while sending the threats to 70 schools in Bengaluru a few days ago.

He said a Russian-based domain, mail.ru, was used to send the threats to schools in Delhi and Ahmedabad.

These emails are being sent using proxy servers or a VPN (virtual private network), the officer said.

Police said it is suspected that the purpose behind sending such emails was to trigger panic and disturb public order in metro cities amid the Lok Sabha polls.