The accident occurred around 2am on Thursday on the Hatikumrul-Bogra Highway’s Royhati area, said Hatikumrul Highway Police Station OC Abdul Quader Jilani.
The deceased have been identified as Suleiman Hossain (65), his daughter-in-law Lily Akhter (35), her son Sagor (12) and microbus driver Abdul Khalek (32).
Another of Akhter’s sons, Shobuj (18), and her nephew Monsur Rahman, were injured in the accident.
Rashid works in Malaysia and was flying home on his holiday.
The microbus collided head-on with a bus in Raiganj Upazila’s Raihati area.
Three of the victims died on the spot. Three others were injured.
Microbus driver Abdul Khalek died on the way to the hospital, said the OC.
The injured have been admitted to Sirajganj Sadar Hospital for treatment, he added.