The accident in Rajshahi’s Paba Upazila leaves two other motorcyclists injured
Police suspect there were three people including the driver in the car, which went underwater in minutes around Friday midnight.
Munshiganj Sadar police OC Yunus Ali said the car had lost control after crossing the Muktarpur Bridge's toll plaza and then hit the west side railing before going over.
The car had at least three people in it, he said based on the CCTV footage of the toll plaza.
Ali said Fire Service divers had reached the scene to conduct a rescue operation, but that did not start until 2:30am Saturday due to strong current in the river.
He added that a diver team was summoned from capital Dhaka and the rescue efforts will follow at the earliest possible opportunity.