RAWALPINDI, Oct 8 Two American FBI agents, investigating terrorist attacks in Islamabad, visited a Rawalpindi police station on Thursday and collected samples from a cache of arms and explosives that the city police had seized in a raid on a terrorist den in January.

Tight security measures were taken by the Saddar Bairooni Police Station for them and nobody was allowed inside during their 90-minute stay there. A Pakistani employee of the American Embassy accompanied the two agents, one male and a female, on their probing visit.

Regional Police Officer Rawalpindi Muhammad Aslam Khan Tareen confirmed their visit and examination of the explosives seized by the police.

“They just wanted to examine it and compare it with (explosive) material they already had,” the Additional Inspector General of Police said.

A law enforcement officer familiar with the probe told Dawn that the FBI team minutely examined “the case property” - that is the materials the police had seized in their raid on the terrorists' hideout in Dhoke Lakhan locality on 29 January 2009.

These included explosives, detonators, potassium chlorate, hand grenades and two motorbikes.

Police had also arrested nine alleged terrorists in the raid, while a tenth suspect had fled the scene, leaving behind a bag containing some explosives.

They all belonged to Wana, South Waziristan. Police were still investigating the case when the FBI agents arrived, showing interest in “the case property”.

Since the FBI had been investigating last year's terrorist attacks on the Luna Caprese restaurant and the Marriott Hotel of Islamabad, it is believed the agents wanted to match the explosives used in those attacks with those seized in January this year.

A Turkish nurse, employed by the Americans, was killed and four FBI agents were reportedly injured in the grenade attack on Luna Caprese, carried out on March 15, 2008.