But even in a country that has become increasingly numb to such attacks, the Dhaka cafe siege
that left at least 20 hostages dead Saturday left the nation stunned.
While ISIS quickly claimed responsibility for the attack, some experts say al Qaeda in the Indian Subcontinent (AQIS) is more likely behind the bloodshed, raising concerns that rival terror groups are trying to outdo one another and establish dominance in the region. The rocky political landscape has not helped much, and has only created room for extremist groups to flourish.
Terrorism in the Muslim-majority country can be broadly divided between two groups and their affiliates: Jamaatul Mujahideen Bangladesh (JMB) is a local ISIS affiliate, while Bangladeshi extremist groups such as the Ansarullah Bangla Team (ABT) follow AQIS.
ISIS claimed responsibility for the Dhaka attack via Amaq, its de facto news agency. But some U.S. officials doubted the claim.
But ISIS claims responsibility for many attacks, and analysts say sometimes the links between events and the groups are tenuous.
The platform ISIS uses for claiming attacks can offer hints to whether it was a plot planned by the group's central leadership or simply inspired by ISIS, terrorism expert Sajjan Gohel said.
An Amaq announcement, similar to one issued after the Orlando nightclub shooting and the assassination of a French police chief, is typically used when it does not come from the group itself.
"If ISIS claims responsibility through Amaq, it tends to be more followers that were inspired by ISIS who may have had some degree of communication but not necessarily have been to Raqqa, Syria, training with them," Gohel said.
"If the claim is made through a Telegram channel, it is very much directed by them such as in Paris. Radio broadcasts they use when they kill Muslims in the Middle East," he said.
"It would imply (this attack) was more opportunistic, but it's not a hard and fast rule, it's an indicator."
Al Qaeda in the Indian Subcontinent
Based on past operations, it is more likely that al Qaeda in the Indian Subcontinent conducted this attack -- not ISIS, a U.S. official told CNN's Barbara Starr.
While this was a preliminary assessment based on information developing at the time, the official says AQIS has demonstrated a more capable presence in Dhaka over the past few months than ISIS. So far, all its attacks in Bangladesh have been in the capital.
"It will be interesting to see how AQIS reacts to ISIS' claim," Gohel said. "There are instances in Yemen where they compete with each other as to who can kill more."
While terror group alliances can shift -- one terror outfit Ansar al Islam for instance started out with close ties to al Qaeda but later merged with ISIS. Gohel said those distinctions are sometimes moot.
"People say, well it's not ISIS-controlled or al Qaeda-controlled, but the point is ABT is inspired by al Qaeda and JMB by ISIS."
Jamaatul Mujahideen Bangladesh
By far the most prominent of the local jihadist groups, the JMB pledges its allegiance to ISIS. Its attacks have focused on religious minorities, such as Hindu clerics
and nonmajority Muslims from Shiite, Ahmadiyya and Sufi communities.
Ansarullah Bangla Team
ABT is the al-Qaeda affiliate in Bangladesh. It was the group that sent out a hit list of 84 "atheist" bloggers
, and led to the murders of writers like Avijit Roy
and prominent LGBT activists
. Much of its violence has been aimed at silencing liberal and secular voices.