The missing policeman was identified as Musa Ali of Chachai village.
According to fire service officers, Musa along with six family members had been on a pleasure trip in the river.
When they were returning home around 7 pm, the engine of their trawler turned dysfunctional.
At one stage, the trawler sank as it hit an under-construction bridge due to strong current in the river.
The father along with the son remain missing after the incident while others were rescued by locals.
On information, a team of Lohagara Fire Service went to the spot and conducted rescue drive at night.
However, the team could not trace the missing father and son till Saturday morning.
Meanwhile, a team of divers from Khulna is expected to join the rescue drive.
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