The accident took place on the Dhaka-Aricha Highway around 6:15am on Friday, said Borongail highway police outpost In-Charge Sergeant Yamin Uddoula.
All the victims were passengers of the pickup.
The police sergeant identified the deceased as Shefali Begum, her daughter Nargis Aktar, Mizanur Rahman and Poran Rajbangshi.
He told bdnews24.com the Dhaka-bound bus collided head-on with the Paturia-bound pickup in the Upazila’s Tora area.
Shefali and Nargis died on their way to the hospital, Sergeant Yamin said.
Six other wounded, including Rahman and Rajbangshi, were also rushed to a local hospital and Manikganj Sadar Hospital.
The two died at the Sadar Hospital while undergoing treatment.
Drivers of both vehicles had fled right after the accident, the police officer said, adding that they had impounded the bus and pickup.