Tirunelveli District Police, assisted by cyber crime experts from Chennai, have secured five people for questioning in connection with Friday's e-mail threatening to blow up the Parliament, the American Embassy in Delhi and Consulate in Chennai.

Police sources told UNI Saturday no arrests had been so far made and the person who had sent the mail was yet to be traced.

Meanwhile, a special team of Delhi police left New Delhi to the southern district of Tamil Nadu, to probe the e-mail threat, which had originated from a cyber cafe in Tirunelveli.

The investigation was all set to gain momentum with the arrival of the team from Delhi and a two-member special team from Chennai headed by Assistant Commissioner of Police Cyber Crime Balu.

The proprietors of two internet cafes in Palayamkottai town were among the five people secured for interrogation.

Soon after intelligence information that the e-mail message was sent from Palayamkottai, police swung into action and picked up Selvyn Muthuraj of Broadband Net Cafe and Raj Babu of Nellai Online for questioning.

People working in these two Internet centres were also questioned about the arrival of visitors and to ascertain the names of those who frequented the cybercafe. Regular visitors who used to come to the internet centre to browse were also being identified and questioned.

A special police team raided the two browsing centres Friday night.

Senior police officials, including the deputy inspector general, superintendent of police and Tirunelveli City police commissioner were present at the raids.

Police have also sought the services of software experts to trace the origin of the e-mail message.