Earlier, on the same night, the same gang of pirates belonging to Alauddin Bahini looted merchandise valued at about Tk one lakh from five boats on the Tetulia river, police said.

At least 20 fishermen and traders were injured in the attacks. Nine of them have been admitted to Mohipur and Kalapara hospitals.

They are Zafar, 24, Amin, 30, Shahana, 32, Farid, 33, Kawsar, 35, Alamgir, 30, Solim, 28, Nasir, 34 and Moazzem, 26 all from different villages in Kalapara upazila.

The pirates fled towards Bhola in four speed boats. Kuakata ferry police also confirmed the incidents.

Fishing in the Bay and off-shore areas have become risky because of frequent incidents of piracy. Alauddin, the ringleader of pirates in the area is from Gajaria village in Lalmollah upazila in Bhola district, sources said .

Police said they can not take any effective action due to lack of logistics including speedboats.