In Dinajpur town, three members of a family died when an oil tanker ploughed into a motorcycle around 5:30 am on Wednesday, Kotwali Police Station Sub-Inspector Krishna Roy said.
Hossain has been admitted to the M Abdur Rahim Medical College Hospital in critical condition.
The family was travelling to Hossain's village in Chapainawabganj's Bholahaat Upazila on a motorcycle to celebrate Eid-ul-Azha when they met with the accident, according to the police.
The driver of the oil tanker fled the scene after the incident. Police are trying to track the vehicle down.
The bodies were sent to the hospital's morgue for autopsies.
Meanwhile, another motorcycle rider, Shahidul Rahman, died after a bus hit his two-wheeler on the Dinajpur-Birganj Road around 8 am, said Birganj Police chief Subrata Kumar Sarker.
The victim worked at the land office in Parbatipur Upazila's Mostafapur.
Shahidul was on his way to Parbatipur from Birganj when the accident occurred. His body has also been sent to the hospital for an autopsy.