Sleuths of the Intelligence Bureau and Kerala [Images] police are carrying out countrywide raids to the catch the person who sent the threatening e-mail to Prime Minister Dr Manmohan Singh [Images]. Three persons, including the owner of the cybercafe from where the e-mail was sent, have already been taken into custody.

"We are not leaving anything to chance. We are on the job to nab the sender of the e-mail," a senior intelligence official told rediff.com on Friday evening.

But another intelligence officer said that though the IB is not taking the threat lightly and every possible angle is being looked into, the Kerala police has gone overboard in telling the media about it and the media in turn has exaggerated the incident.

"Such incidents are dealt in absolute secrecy so that no panic is created among the general public," the official said.

Union Home minister Shivraj Patil and other senior ministers in the home ministry and top officials of the Prime Minister's Office and home ministry are being kept in the loop about the latest developments.

Dr Singh would visit Kerala on November 1 despite the e-mailed threat to his life, the Prime Minister's Office said in New Delhi.

Three persons were arrested by the Kerala police after an e-mail was received by the Prime Minister's Office from a cyber cafe in Kochi saying that there would be a threat to the prime minister's life during his visit to Kerala. This includes two boys who were customers and had used the cyber cafe between 9 and 9.30 on Friday morning and the owner of the cafe who is a woman.

Several senior officials, including the home secretary and DGP received the e-mail sent from the same ID on Thursday. 

It contained references to Mohammed Afzal Guru, facing execution for the 2001 Parliament attack, and PDP leader Abdul Nasser Madani, who is being held in connection with the Coimbatore blasts.

State Home Minister Kodiyeri Balakrishnan, who hurriedly convened a meeting in Thiruvananthapuram of top officials including the DGP, chief secretary and home secretary, said there was no reason to panic but the government had taken serious note of the matter.

Kerala Chief Minister V S Achuthanandan said his government was viewing the e-mail issue "very seriously". He said the state police chief was looking into the matter and senior police officials would keep him constantly informed about the progress of investigations in the matter. Asked if any foreign hand was suspected in the matter, Achuthanandan said police are looking into all aspects.

Kerala police is interrogating the accused to find out if they had played a prank or were they really aware of any serious threat to the prime minister during his forthcoming trip.

"As of now there is no change in the prime minister's trip, but his security is being constantly under review and a decision could be taken keeping in the mind threat perception," a senior official of PMO told rediff.com on Friday afternoon.

Minister of State for Home Sri Prakash Jaiswal told newsmen in Kanpur that raids are being conducted at various places to unearth the conspiracy behind the e-mail.

President A P J Kalam had also received a death threat recently and the person in question was arrested. Some time back an e-mail was sent from Tamil Nadu threatening to blow up Parliament but it turned out to be a prank.