Indian security agencies are now investigating four e-mails claiming credit for the Delhi High Court blast, but the question remains as to whether the e-mails are merely a prank or a strategy to confuse investigators, reports CNN/IBN.

Here's the channel's recap:

The first e-mail was received on the day of the blast, i.e., Wednesday, September 7, allegedly sent by the Harkat-ul-Jihadi to media houses, claiming responsibility for the blast.

On September 8, the second e-mail surfaced, allegedly sent by Chhotu Minani Ayushman on behalf of the Indian Mujahideen claiming responsibility for the blast and threatening more in public places.

Then on Friday, the Delhi Police received another e-mail from 'I'll kill Indians @ yahoo.com', sent as a numeric code. The mail threatened to attack Ahmedabad.

And then late on Friday night, another e-mail from Chhotu Minani claimed that Ahmedabad will be attacked in a way that police will not be able to find any evidence.

So far, police have arrested a college student in Jammu & Kashmir for sending the first email claiming responsibility for the blast, which claimed to be from the Harkat-ul-Jihad Islami. The authorities have traced the second e-mail, supposedly sent by the Indian Mujahideen, to West Bengal, and the proxy server for the third e-mail has been traced to Moscow, the news channel said.

No corroborating evidence linking the emails or their senders to the bomb blast has surfaced.