The police and members of Rab-1 in the three-hour raid picked up 10 people from crime-infested slum. Four of them were arrested for their suspected link to the arms and ammunition cache and the rest were released after interrogation.

Sources at the police and Rab said they have retrieved 25 shotgun cartridges and 10 .303 rifle bullets abandoned in a shanty. However, it was not immediately known who owns the shanty.

Intelligence officials believe Mukul, a suspect of the August 21 grenade attack, and his gang are linked to the grenades and firearms seized on Monday.

Mukul is now on the run as he is a chargesheeted accused in last year's Badda grenade, time bomb and firearms case and has close ties with Imam Hossain, one of the top 23 police-listed criminals who controlled Sattola slum and nearby TB Hospital slum. The slums are hotbeds of drug peddling and gunrunning, sources said.

Investigators and locals said the cache seized on Monday was under the possession of Mollah Shamim, who was the second-in-command of Imam, a former joint secretary of Dhaka City north unit of Jatiyatabadi Chhatra Dal.

Intelligence officials stepped up their drive to search out Mukul after a video footage confirmed his presence at the AL rally on August 21.

Sub-inspector Jamal Uddin of Rab team filed two cases under Arms and Explosives Acts with Gulshan Police Station yesterday. He accused Abul Kashem and Akkas, whom Rab claimed to be the owners of the shanty.

The bloodstained copies of newspapers and some news clippings on the August 21 grenade attack have reinforced the investigators' suspicion, another official said.

Deputy Commissioner of North Zone of Dhaka Metropolitan Police Golam Rasul said they are suspecting Mukul's link to the seized cache.

Police recovered four AK-47 assault rifles, two revolvers, 20 hand grenades, four time bombs and huge numbers of AK-47 bullets and explosives after a gunfight with a criminal outfit at Kuril Badda last year.

Residents of Dakkhinpara in Sattola slum said two dark-complexioned, medium-sized men aged around 40 lived in one of Kashem's shanties. The shanty had a secret passage where the cache was seized from.

"Some people including Mollah Shamim visited the two men and stayed there for long," said a neighbour of Kashem, wishing anonymity.

Kashem was a night guard at the Infectious Diseases Hospital which is surrounded by Sattola slum. He lived in a room of the slum with his wife, a sari vendor, a son and a daughter. He moved elsewhere with his family after Mollah Shamim was arrested and killed in a 'crossfire'.