Robbers looted at least 25 vehicles on the Dhaka-Dinajpur highway in Nawabganj upazila of the district in the early hours of yesterday.
The firearms they used in the robbery were of Highway Patrol Police, said Dinajpur police.
Ahead of the robbery, 10 to 15 men around 1:30am held hostage highway policemen Sub-Inspector Golam Mawla, a second officer of Nawabganj Police Station; and two constables Mokhlesur Rahman and Hafiz Uddin, took away their firearms and tied them to roadside trees.
The robbers then stopped vehicles by blocking the highway at Bhaduria village with logs and robbed their passengers of valuables and cash at gunpoint. The looting continued until 5:00am yesterday.
The gang also stabbed at least three people including a bus driver. Of them, Nitai Chandra Roy, 45, of Rajbari in Dinajpur municipality, was admitted to Dinajpur Medical College and Hospital in a critical condition, hospital sources said.
Nitai said he was going to Dhaka in a passenger bus when the incident took place.
The district police department would not give details of the robbery but said they had recovered all the looted firearms.
However, passengers of vehicles stuck in traffic jam on the highway following the incident said policemen had been conducting a massive search for the missing firearms.
One of the firearms was later found about 50 metres from the scene, locals said.
Babul Ahsanul Kabir, chairman of Bhaduria Union Parishad, said quoting village policemen that the robbers had looted cash and goods worth Tk 4 lakh, assaulted at least 15 people and stabbed at least three others.
Biman Karmaker, assistant superintendent of police of Phulbari circle, Dinajpur, confirmed that the highway policemen including SI Golam Mowla had been on duty during the robbery.
On information, a police team rushed to the spot and helped resume the road communication around 5:40am, villagers said.
Meanwhile, some high officials of Dinajpur police department visited Dinajpur Medical College and Hospital in the morning to inquire about injured Nitai Chandra Roy.
They asked Nitai to tell journalists that the missing firearms had been recovered.
Imrul Kayes, officer-in-charge of Dinajpur Nawabganj Police Station, said three to four passenger buses were looted yesterday, which contradicted the statements of locals and the victims.
The OC added Dinajpur police were interrogating the policemen on duty, who had been rescued by some passengers and locals after the incident.