However, officials claimed that investigation is in progress and it is nearing completion in at least one case.

Charge sheet in the twin blast in cinemas will be submitted soon, they said.

The much talked about incidents include the bomb blast at the shrine of Hajrat Shahjalal (RA) during Urs in January 12, grenade attack on British High Commissioner Anwar Chowdhury after Juma prayer on May 21, bomb blast at the meeting of Awami League (AL) stalwart Suranjit Sengupta MP in Sunamganj on June 21, grenade blast at a meeting of city AL on the night of August 7 and blasts in two cinemas in the city on August 5.

Those killed included a Sub-Inspector, an AL leader and a party activist and a street urchin.

Five of the six cases were transferred to CID (Criminal Investigation department), now being probed by an ASP, engaged on a two-year contract after expiry of LPR (leave preparatory to retirement). This raised questions in the police department, sources said.

Police arrested at least 50 people in the January 12 Shahjalal shrine blat case, but failed to make any significant clue. Later, the case was transferred to CID.

Police picked up 30 people after the May 21 grenade blast that killed Sub Inspector Kamal Uddin and injured 70 people including the British High Commissioner, but could not make any headway in the probe.

Investigators from Scotland Yard visited the shrine several times.

The then Police Superintendent was suspended and withdrawn from Sylhet on charge of negligence in duty during the British High Commissioner's visit to the shrine.

The Investigation Officer made trips to Singapore and London to quiz an injured person being treated there. But nothing significant was found.

Street urchin Shahad,11, was killed in Rangmohal cinema hall blast in the city on the night of August 5.

Police are preparing to show the 11-year boy as the carrier of the bomb and prime accused in the incident. The charge sheet will be soon, said an official.

Soleman, believed to be the bomb carrier in the other cinema blast incident is now a crippled man from injuries.

The CID interrogated at least 60 people including Awami League leaders and activists in connection with the grenade blast at a sports car on the premises of Gulshan Centre on the night of August 7.

The blast took place minutes after the departure of city Mayor and AL leader Badar Uddin Ahmed Kamran following a party meeting there. Ibrahim Ali, city AL Publicity Secretary and a close associate of the Mayor and 30 others were seriously injured in the blast.

On the other hand, police took AL leader and Bangladeshi expatriate SM Nunu Miah into custody immediately after the blast. Police allegedly tortured him. Nunu was later released at the intervention of British MP Oona King, who came on a short trip to Bangladesh.

AL later alleged there had been attempts to implicate party leaders and activists in the incident.