The terrorists who attacked the prestigious Indian Institute of Science in Bangalore had brought grenades manufactured abroad for triggerring off explosions, a preliminary probe has revealed.

A thorough examination of the HD 84 grenades left behind by the culprits indicated that they were manufactured in a foreign country, Karnataka DGP B S Siyal told PTI.

He said, though eyewitness accounts at IISc maintained that there was a lone terrorist, police believe it could be at least two or three and that more than one weapon was used in the firing, which killed Indian Institute of Technology, Delhi Professor M C Puri and wounded four others.

Siyal said the suspicion of the police that more than one weapon was used has been strengthened by the fact that the pellets found in the eye of Sonia Gupta were different from those used in an AK-47 rifle. The police have been exchanging information with their counterparts in Chennai, Kolkata, Mumbai and Delhi, he said.

• IISc: Stirred but not shaken

The recovery of dry fruit from the kit of terrorists suggests that they were not locals, Siyal said. Confusion continued to confront police on the type of vehicle used by terrorists, as the IISc campus is located in a busy locality.

Meanwhile, a top military official said the failure of the defective grenades forced the terrorists to flee from the scene for safety and thus prevented higher casualties.

General Officer Commanding, Major General B Shivashankar, who spoke to reporters on the sidelines of the Civil Military Liaison Conference 2005, said that when the grenades failed to explode, fear gripped the attackers.

He said that once the pin of the grenade is opened and it is lobbed, it should explode. In the IISc terror attack, the device failed to explode as it was defective, he added.

• Bangalore police play blame game

The police have recovered four grenades, with the pin of one opened. Had the grenades exploded, the number of casualties would have been more.

Shivashankar also alleged that there was free movement of Naxals from Jharkhand, Bihar and Andhra Pradesh and wanted the government to step up intelligence and security cover.