The Delhi Police has written to the CBI seeking information through Interpol channels about a hoax bomb threat e-mail sent to more than 150 schools in the National Capital Region (NCR), officials said on Thursday.

The Central Bureau of Investigation (CBI), the designated National Central Bureau of India and also known as Interpol India, is responsible for all the communication and coordination with the Interpol, they added.

The agency is likely to forward the information sought by the Delhi Police to the Interpol, which in turn will send it to all the member law-enforcement agencies of the world, the officials said.

The Delhi Police is investigating the IP address used to sent the e-mail, besides the sender and origin of the mail to decipher the conspiracy and motive behind the hoax threat that resulted in panic across Delhi-NCR on Wednesday.

The mail purportedly sent from a mail.Ru server claimed that explosives were planted on the school premises, triggering massive evacuations and searches as panic-stricken parents rushed to pick up their children. The threat that sent alarm bells ringing in the security establishment was later declared as hoax as nothing objectionable was found from the campuses.

The officials said an initial probe has led to the suspicion of a "deeper conspiracy" hatched by a terror group during the ongoing Lok Sabha polls, adding that the threat mail could have been sent by an ISIS module.

The Delhi Police suspects that the mail was sent using the VPN and dark web -- an encrypted online content platform that allows individuals to hide their identity and location from others.

A case has been registered by the Special Cell of the Delhi Police under the relevant legal provisions for offences like conspiracy and threat and a dedicated team formed to conduct the investigation, an official said.