"Anurag has been arrested for sending a threat mail, he send the mail by creating an account in name of his neighbour Manish Sharma," a police official told IANS over phone.

The engineer wanted to get his neighbour Manish implicated in a false case, the official added.

According to police, the e-mail was sent to the mail id of Delhi police commissioner June 2. Sent in name of Baidaihi Sharma, a resident of Aryana colony of Hazaribagh, the mailer said he was the brother of dead CCL employee Ramesh Sharma.

The mail threatened the prime minister and home minister if Ramesh's retirement benefits were not given to family members, police said.

On interrogating the Sharma family, the police discovered that none of the family members were working in CCL.

Police arrested the cyber cafe owner Adib Hasan June 7.

The IIT Kharagpur engineer has worked for five years in US and Mumbai.