An unnatural death case was filed with the Jhalokathi Sadar police station over the launch fire incident on Saturday.
Jhalokathi Sadar police officer-in-charge Khalilur Rahman said that village police member Jahangir Alam filed the case.
At least 37 people were killed and over 100 injured as a launch carrying hundreds of passengers caught fire on Sugandha River at Gabkhan-Dhansiri area under Sadar upazila in Jhalakati on early Friday.
Most of the victims were burned to death while a few others were killed as they jumped into the river in a desperate attempt to avoid the flame, rescuers and survivors said.
The authorities have suspended the rescue operations for missing passengers at 6:00pm but said they would resume the work Saturday.
Officials said the fire started at 3:00am, reportedly from the engine room, and spread soon in the three-storied MV Avijan-10, leaving passengers, most of who were, sleeping off-guard.
The launch, which was travelling to Barguna from the capital Dhaka, was in the mid-river when it caught fire.
