The West Bengal Police have detained four persons,suspected to be behind one of the emails that claimed responsibility for the Delhi High Court blast. NIA sources said that the sender of the email from chottominani@gmail.com id appeared to have hacked into the cellphone account of a person and used the phones mobile-office service to send the email. The NIA officials said they did not attach much importance to the third email sent from Gujarat,for which the Ahmedabad Police had arrested 24-year-old Monu Brahmanand Oza. The police picked up Oza for questioning three days ago and registered an FIR against him under various sections of the Information Technology Act on Monday. This email was received on the night of September 8 by the Delhi Police on delpolice @nic.in and claimed responsibility on behalf of the Indian Mujahideeen. Police said Oza had confessed to sending the email but claimed that he did this to ensure security was stepped up in Ahmedabad the email,in a coded message,warned that Ahmedabad was the next terror target to prevent any attacks. While NIA officials were making efforts to trace the IP address of the fourth email sent from Bengal,they said the lead in the Kishtwar e-mail,which claimed the blast was the handiwork of Harkat-ul-Jihadi,appeared to be the strongest and was being pursued. As reported by The Indian Express on Monday,the NIA brought the hard disks of the computers of the cyber cafe in Kishtwar,from where the email was allegedly sent,to Delhi for forensic examination. The NIA and the J&K Police have detained for interrogation several persons from Kishtwar,including a youth who is suspected to have sent the mail. Investigators believe the other emails,including the one purportedly from the Indian Mujahideen,appeared to be only pranks. Meanwhile,the J&K Police,who are helping the NIA in the probe,have detained seven people in connection with the Kishtwar email. NIA is investigating the incident. We are providing due support to them, DGP Kuldeep Khoda said.