The age of the deceased is believed to be around 35 years.
Abdullah Al Mamun, officer-in-charge of Barishal Sadar river police station, said that Parabat-11 launch reached from Dhaka in the early morning.
When the launch staff members were checking the cabins after all the passengers had left, they spotted the body in cabin 391.
The cabin was booked by a man using a fake mobile phone number.
The body was sent to Kotwali Police station, said the OC adding that legal action would be taken after autopsy.
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