Locals say Sunni and Shia Muslims have been living there in harmony for around three decades without any religious discord. The attack has stunned as well as confused them because no such incident had ever taken place there before.

The residents have no clue why the assailants would open fire on people praying inside a mosque.

According to witnesses, three attackers sprayed bullets on the Muslims while they were offering Maghrib prayers on Thursday.

The mosque’s Muezzin Moazzem Hossain, 70, was shot dead. Imam Shahinur Rahman, 60, local residents Taher Mistri, 50, and Aftab Ali, 40, were injured.

People were gathering at the Al Mostofa mosque since early Friday morning. Stains of blood and bullet holes on the pillars were reminders of the horror.

Panic was palpable as only three people attended the Fazr prayers at that mosque next morning, locals said.

Detective police and RAB officials have been deployed around the mosque since the incident.

A case was filed with Shibganj police over the attack Thursday night, accusing unidentified assailants.

The law-enforcers on Friday said they had detained two persons for questioning in connection with the shooting.

Militant group Islamic State is claimed to have assumed responsibility for the incident.

A Shia organisation, Bangladesh Imamia Welfare Foundation, is housed in the premises of that mosque, known as the Al Mostofa mosque.

Abu Jafar, a freedom fighter, is the chairman and Md Mozaffar Hossain is the general secretary of the organisation.

Hossain told bdnews24.com: “There is no animosity between the Shias and Sunnis of this area. Shias built the mosque, but devotees from both sects say their prayers here. There has been no problem until now.”

“The incident of shooting has created massive panic among the Shias. The deceased muezzin was a good person. He had no enemies.”

Abu Jafar said there are at least 110 people currently living in the area who follow the Shia ideology.

The Shias who live at Haripur, Challishchhatra, Aladipur, Gopinathpur, Ramkandi and Belail villages in Shibganj Upazila’s Kichok Union, attend prayers at Al Mostofa mosque.

Shia Muslims from several areas of neighbouring Gaibandha’s Govindaganj Upazila also come here to say their prayers.

Abdur Rashid, a Shia Muslim from Haripur, told bdnews24.com that he and his cousin Idris Ali, who is a Sunni, live next to each other.

“We have never had any dispute. Just like us, other Shias and Sunnis, too, have been living peacefully here.”

Haidar Ali, a Sunni from the same village, echoed Rashid. “All of us are always on good terms.”

Abu Jafar said, “We are stunned by the incident. We don’t harm anyone. Why did this happen? We are in panic.”

But some guest speakers who would come to attend different Islamic programmes tried to instigate the local devotees by calling the Shias ‘kafirs’, a derogatory term in Islam used for disbelievers, he alleged.

“Several years ago, Imam Maulana Ashraf Ali Siddique of Katnar Parha’s Kuba Mosque in Bogra City made such remarks when he addressed an event at Shibganj. He also attends such programmes in adjacent areas.”

He thought Siddique’s remarks could have played a role in instigating Thursday’s shooting.

Bogra’s Superintendent of Police Md Asaduzzaman on Friday told bdnews24.com: “Shia haters might have carried out the attack. But we are investigating keeping other angles in mind.”

“Islamic State has allegedly claimed responsibility for several recent incidents. But investigations revealed that IS was not involved in any of them.

“We, too, are yet to find anything that indicates the Islamic State was behind this attack,” he said.