An email a day has been foxing the security agencies probing the Delhi High Court blast as they are unable to decipher whether the electronic messages were a prank or a modus operandi used by terror groups aimed at confusing the investigations.

The email received by Delhi Police headquarters late last night is claimed to have been bounced from various Internet gateways with the server finally traced to Moscow, official sources said.

They said earlier it was not clear whether the mail could have been masked and shown to have been sent using the Russian server but later it was found that server and Internet gateway from that country had been accessed to send the mail to police headquarters claiming more attacks.

The probe agencies were seeking assistance from other security agencies to track the end-user of the mail who used domain name of Yahoo to send the mail by creating an account "killindian@yahoo.com".

The first mail was received two hours after the blast and the Internet Protocol address was traced to Kishtawar in Jammu region. The cyber cafe owner and manager were questioned thoroughly and the police and NIA team had made a sketch of the possible suspect who had sent the mail using the Gmail service provider and named "Harkat-ul-Jehad" as responsible for the attack.

The second mail was received by media houses yesterday in Delhi and Mumbai claiming that the blasts were carried out by Indian Mujahideen. This mail has been traced to Kolkata.

With the government making it clear that all mails were being treated seriously, the investigators were at present busy tracking the senders of the mails.