The deceased were identified as Nupur Begum, 30, wife of Abul Hossain, their daughter Lamia, 15, and son Nishad, 10, residents of South Raogaon in the upazila.
Witness said the bus hit a microbus as its driver lost control over the steering near a speed breaker at the school intersection.
The bus also hit two auto-rickshaws and seven pedestrians, leaving the trio dead on the spot around 11:30 am, said Md Abul Bashar, officer-in-charge of Amtali Police Station.
Victim Nupur’s aunt Baby Akther said the tragic accident occurred when Nupur along with her son and daughter were returning home from their relative’s house in the morning.
On information, police recovered the bodies and sent those to Barguna Sadar Hospital morgue for autopsy while the injured were admitted to Sher-e-Bangla Medical College Hospital.
Police seized the killer bus but its driver managed to flee the scene,the OC added.