Three passengers of a battery-run auto-rickshaw were killed when a bus hit it on Dhaka-Kuakata highway in Barguna's Amtali AK School area on Saturday morning.
The deceased are Nupun Begum, 32, her son Haseeb, 12 and Lamia, 14.
Three more were injured in the accident.
Police and eyewitnesses said that a Potuakhali-bound bus named "Mayer Doa" crashed into the auto-rickshaw in the morning. The bus also bumped onto a microbus before it got stuck on a roadside electric poll.
Later, the police and local people rescued the auto-rickshaw passengers and took them to the hospital at Amtali upazila when doctors declared the three dead.
The injured were sent to Barisal for better treatment after first aid.
Amtali Police Station Officer-in-Charge Md Abul Bashar said, "The bus has been brought to the police station. We are trying to arrest the bus driver and helper. Preparations are underway to send the bodies to Barguna General Hospital morgue for autopsy."