Law enforcers claim they have largely contained militancy through close monitoring and regular drives for the last seven years. Still, small splinter militant groups continue to pop up and carry out criminal activities.
Sunday's armed attack on a prison van to snatch three JMB members is the work of such a group, according to sources in law enforcement and intelligence agencies.
The murder of blogger Ahmed Rajib Haider in February last year and the six murders in Gopibagh on December 21 are two other instances.
Many fugitive militants as well as those released on bail are trying to reorganise through these small militant groups with new names, said an intelligent official wishing anonymity.
Besides, the banned outfit Hizb ut-Tahrir is still active, he added.
The seven NSU students accused of killing blogger Rajib were initially suspected to be Tahrir members. Later, they were identified as members of a new group Ansarullah Bangla Team, headed by Mufti Jasimuddin Rahmani, who is also a charge-sheeted accused in the Rajib murder case.
Detectives say Jasimuddin had connections with international terrorist organisations, which is a matter of concern, especially after the arrest of three Pakistanis last month with manuals on bomb making.
The Pakistanis' main aim was to revitalise the weakened militant groups in Bangladesh, a DB official told The Daily Star.
The murders of controversial religious leader Lutfar Rahman Faruque and his five followers on December 21 might have been committed by a small fanatic group over his interpretations of religion, said Inspector Abual Khayer Matabbar, investigator of the case.
"Lutfar made many enemies for his off-track religious practice and preaching of faith," he added. Lutfar had published three books on his interpretation of Islam.
Following the posting of an audiovisual message purportedly by al-Qaeda chief Ayman al-Zawahiri urging Bangladeshi Muslims to wage intifada, the Rab last week arrested a student in Tangail for “spreading” the clip online.
Director General of Rapid Action Battalion (Rab) Mukhlesur Rahman said, "We are checking out if it is really a statement by Zawahiri". However, he said it is not unlikely that Zawahiri's followers are present in the country.
"There are some scattered militant outfits but they are under our control. The people of this country are not supporters of religious extremism and so militancy can never rise as it did in Afghanistan and Pakistan," the Rab DG added.