The blasts, especially in the north of the country, have stamped terror on the faces of the people who barely witnessed such incident before.

Intelligence operatives probing the blasts suspect that Islamist militants, who all too often speak against jatra and variety shows featuring gambling and various amusements, might have been involved in the attacks, particularly those in the northern part of the country.

The Inspector General of Police Ashraful Huda yesterday told The Daily Star that the investigations are on and it still cannot be said who were behind the blasts.

Bogra police on January 17 arrested Shafiqullah with bomb-making materials at the house of alleged Jagrata Muslim Janata Bangladesh follower Joynal in Gabtoli upazila. He admitted to be a member of Jamiatul Mujahidin. He denied his involvement but said his fellow cadres carried out Saturday's bomb attack in Bogra.

In the last two months six incidents of bomb blasts in village fairs, cultural functions and jatras in Bogra, Natore, Jamalpur, Sherpur and Pabna districts had left two people dead and 145 injured.

Members of intelligence agencies investigating the blasts said two attacks in Bogra and one each in Pabna and Natore districts bore the hallmarks of Islamist militant attacks.

"Islamic zealots, who express strong opposition to traditional cultural shows, are very much likely to have made the attacks," said a top official of an intelligence agency on condition of anonymity.

He said a number of people arrested recently with explosives in the northern regions admitted to having links to Islamist militant groups and these confessions have only strengthened the belief that religious extremists might have orchestrated the violence. "However, we are yet to find out exactly which organisation was involved and who were the masterminds," he said.

He said followers of Bangla Bhai, the self-styled operation commander of JMJB, could have something to do with the recent attacks in Bogra, Natore, and Pabna. Members of Jamiatul Mujahidin, which once used to be led by Bangla Bhai, and operatives of Harkatul Jihad might also have link to the explosions.

Bangla Bhai, who reportedly killed at least 25 people including a retired army personnel in the northern districts, meanwhile, has been evading capture since the prime minister ordered the law enforcers last year for his arrest.

A top police official tasked with the investigation of the bomb attacks in Jamalpur and Sherpur said they could not yet find any clue to the attacks. They, however, are probing whether there is any link between the attacks in Bogra and Natore and those in Jamalpur and Sherpur.

Biswas Afzal Hossain, superintendent of police in Jamalpur, said, "Besides the religious extremists' suspected involvement, we are investigating the possibilities of internal conflict among the jatra organisers leading to the attacks."

In the first week of December last year police arrested three people at Goarpara in Gaibandha and seized 24 India-made gel bombs, 124 detonators, over 100 other bombs of various sizes and weights.

Explosive carriers Anisur Tahman, Amzad and Sabuj while being grilled at first claimed themselves to be members of Jamiatul Mujahidin, but later said they belong to Harkatul Jihad.

They, however, confessed to carrying the explosives with intent to attack a concert of singer Momtaj, slated for December at Bogra Stadium last year. Police retrieved a bomb on December 22 from Sonatola Pilot High School field where too a programme of Momtaj was scheduled.

The first blast in the series of explosions took place on November 22 when a powerful bomb went off amidst a horse race gathering in Sariakandi upazila of Bogra leaving at least 20 people injured. Nearly a month later, on December 15, a string of similar attacks was carried out at different stages erected for drama, music, and gambling at Kamalpur village of the same upazila. It left 15 people wounded.

On January 12, bombs exploded in two separate cultural functions in Jamalpur and neighbouring Sherpur. Twenty-five people were injured in Jamalpur while at least 10 others, two critically, in Sherpur sadar upazila. On both occasions, cultural functions, in Jamalpur a variety show featuring gambling and in Sherpur a drama festival, were underway when the attacks were carried out.

The latest in the spate was on January 15 in jatra shows in Bogra and Natore where two people died and 70 others injured. Witnesses said in Bogra the bombs were hurled when a female artiste was dancing on stage.