The cellphone believed to have triggered the blast. (PTI)

May 19: The Mecca Masjid blast has thrown up a Bengal link.

Andhra Pradesh police today said the SIM cards of the cellphones used as remote-controlled detonators were bought in Calcutta. The subscriber named in the purchase is believed to be the leader of a Bangladesh-based militant group whose cadre move in and out of Bengal at will.

Three bombs had been planted but only one went off because the SIM cards of the mobiles attached to the other two had expired just a day earlier, a police officer said.

“One bomb exploded when a call was made to one of the phones. But the other two did not take the call because their SIM cards — which were prepaid Hutch cards — had been de-activated. The SIM cards hold vital clues.”

The police said the SIM cards are in the name of Shaheed Bilal, chief of the Harkat-ul Jehadi Islami, who is also believed to be in charge of the Pakistan-based Jaish-e-Mohammed’s operations in south India.

Bilal, believed to be in Saudi Arabia, is a suspect in the Samjhauta Express attack last February and the March 2006 Varanasi temple blast.

The Mecca Masjid toll was today revised to 16. Chief minister Y.S Rajasekhar Reddy said 11 died in the blast and five in the police firing on protesters. Reddy apologised to the families of the firing victims. “I apologise. The police should have been more patient,” he said.

A mob returning from a victim’s burial threw stones at the police in today’s only violent act, injuring two personnel and prompting the force to fire tear gas shells and shoot in the air.

Reddy said his government had withdrawn the Rapid Action Force from Mecca Masjid and stopped video-graphing worshippers because Muslims were feeling insulted.

He said all places of worship “with resources” should follow “the Tirupati model of security”, which includes CCTVs. The state cabinet cleared a proposal to appoint volunteers at every shrine to identify suspicious objects — another feature of Tirupati.

An intelligence source said the bombs must have been planted by a local helper of Harkat or Jaish, probably a sympathiser of Deendar Anjuman or the Students Islamic Movement of India.

Harkat operatives are based mostly in Bangladesh, from where they enter India through the porous North 24-Parganas and Malda borders and carry out strikes, a Bengal intelligence source said. “One of them may have bought the SIM cards.”

Industry experts in Calcutta said it’s possible to track subscriber details — such as the calls made, their duration and destination — thanks to the unique number on each SIM card. “The handsets, thanks to their IMEI number, can also help,” a source said.

“But only people above a certain rank, such as the police commissioner and state home secretary, can ask for such information.”

To get a SIM card, a customer must provide photo identity proof (such as passport or driver’s licence), proof of address (such as a phone or electricity bill) and a passport-size photograph. Physical verification is a must.

But the telecom department admitted a few months ago that connections were being given without proper verification and had asked operators to do a reverification of subscribers within March 31 this year.

A Hutch official would only say that the service provider would “continue to cooperate” with the police.