Investigators are yet to make any breakthrough in 16 of at least 43 grenade and bomb attacks that have taken place in the country since 1999.
Twenty-six such attacks, investigations into which have been successful, were carried out by the banned Islamist militant outfits Jama'atul Mujahideen Bangladesh (JMB) and Harkat-ul-Jihad al Islami (Huji). The JMB is responsible for 17 of these attacks and Huji for the rest, the investigators said.
A number of officials in the agencies investigating the bomb blasts--Rapid Action Battalion (Rab) and Criminal Investigation Department (CID)--said political influence has been a major reason behind the failure to apprehend the real culprits and find out the motives of the attacks.
Political blame game and implicating of political rivals in the cases after many such grenade or bomb attacks have also led to flawed probes and escape of the perpetrators.
The investigators also said the JMB enjoyed the blessings of the BNP and Jamaat-led alliance government in carrying out its vigilante activities in the country's northern region.
A minister of the alliance government even recommended clearing Huji top leader Mufti Abdul Hannan, who masterminded many of the outfit's grisly attacks, of charges for attempting to assassinate Awami League (AL) chief Sheikh Hasina.
The major attacks that still remain unsolved are the bomb attacks on the Ahmadiyya mosque in Khulna on October 8, 1999, on a rally of the Communist Party of Bangladesh (CPB) on January 20, 2001, on a church at Baniarchang, Gopalganj on June 3, 2001, on an AL office in Narayanganj on June 15, 2001, on an AL public meeting at Mollahat, Bagerhat on September 23, 2001, on a cinema in Satkhira on September 28, 2001, the blast near an AL rally in Sunamganj on September 26, 2001, the bomb attack on the Pagla Mela at Shakhipur, Tangail on January 17, 2003, the bomb attack during the Urs of Hazrat Shahjalal in Sylhet on January 12, 2004, and the bomb attack on an AL rally in Sunamganj on June 21, 2004.
Investigators have also no clue to the bomb blast incidents in two cinemas in Sylhet on August 5, 2004, at the Khulna Press Club on February 5, 2005, a St Valentine's Day programme at TSC of Dhaka University on February 14, 2005, the Urs in Narsingdi on March 2, 2005 and Kharampur of Akhaura on August 15, 2005, and three near-simultaneous explosions at railway stations in Dhaka, Chittagong and Sylhet by Zadid al Qaeda, Bangladesh last year.
Failing to get any clue, the investigators have already submitted the final report of the case filed following the blast at the Khulna Ahmadiyya mosque that left eight people killed and 30 injured.
Investigators said they have got a vague picture of the bomb attack on the CPB rally, which left five people killed, as some Huji leaders and activists divulged some information about the attack, said a top Rab official seeking anonymity.
The CID which is investigating the case has already shown 11 Huji operatives arrested in the case and interrogated them during remand but the investigators are yet to get any confessional statement from them.
Earlier, police arrested 12 persons soon after the incident but the CID submitted the final report of the case on December 17, 2003 as correct, impartial and reliable evidence was not found to prove the charges against the arrestees.
The Rab official said the case filed for the attack on a church at Baniarchang is already dead as the police first information report mentioned "crackers" instead of "bombs" that exploded. The blasts, however, killed 10 people and injured 30 others.
After the blasts at the Narayanganj AL office that killed 22 AL leaders and workers, the AL and ruling BNP blamed and filed cases against each other. Two cases filed by the AL accusing 27 BNP leaders and activists including Taimur Alam Khandokar have been closed after final reports were submitted on January 27, 2003.
The proceedings of a case filed against several AL leaders and activists in 2004 were stayed by the High Court. A top CID official said they would file a petition with the High Court soon for orders to continue the investigation.
Investigators have also submitted the final report on the case for bomb attacks on an AL rally in Bagerhat as they failed to find out the perpetrators. The blast killed eight people and injured many others.
Investigators of the bomb blast incidents at Roxy Cinema and a circus in Satkhira in 2001 also submitted the final report on January 31, 2004, showing similar reasons.
Probes into other cases have also failed to achieve any progress.