Investigations by the CB-CID, which is probing the serial blasts, revealed that Musthafa was assigned the task of planting and exploding bombs near the venue for the public meeting of Bharatiya Janata Party (BJP) leader LK Advani.

According to reports, Musthafa was also asked to "carry explosives on his person as a human bomb". However, police officials refused to confirm such reports.

Musthafa has reportedly confessed that he could not carry out the task assigned to him as Advani's flight was delayed and the serial blasts had already begun by the time the BJP president arrived.

Earlier, the CB-CID made a significant breakthrough with the arrest of some of the accused. Based on the confessions of one of them, the sleuths launched a search operation in Melappalayam and Kerala forMusthafa.

Meanwhile, in a crackdown on Saturday, the CB-CID seized documents related to the banned outfit Al-Umma from a house in Al-Ameen Colony in Ukkadam area.

The seized documents include names of people involved in subversive activities, registration numbers of 23 vehicles used for the serial blasts and details of financial operations of the outfit.

Following this, the SIT sleuths have intensified their investigations in the case. According to highly-placed sources, the CB-CID has identified nearly 130 people involved in extremist activities.