He says people with information about the chairman’s location will be rewarded
The attack took place around midnight on Tuesday in the city's Barochon area, said Sakhipur Police Station OC Amir Hossain.
However, police did not make a statement on the possible motives of the attackers.
OC Amir said the police were heading back to the station in a pick-up van after a raid.
“When the van arrived at the Sakhipur-Sagordighi road, the attackers blocked the road with a tree and ambushed police with wooden sticks. They also detonated cocktail bombs. The police fired 19 rounds of bullets in self-defence," said Amir.
The four injured policemen were admitted to the Sakhipur Upazila Health Complex.
Preparations are underway to file a case against the five detainees, said Amir.