The deceased have been identified as Hasad Hossain, 16, from Hatpagla village in Phulphur; Abul Kashem, 50, from Polashtoli, Raipura upazila, Narsingdi; and Ashique Mia, 20, from Satugaon, Nakla, Sherpur district.
According to police and local sources, the accident occurred around 9 a.m. in the Chawrabari area when the autorickshaw crashed into a speeding truck coming from the opposite direction. The impact killed all three passengers instantly.
Three other critically injured passengers were initially taken to Phulphur Upazila Health Complex before being transferred to Mymensingh Medical College Hospital for further treatment.
The truck driver, along with the vehicle, managed to flee the scene, said Md. Abdul Hadi, Officer-in-Charge of Phulphur Police Station. An investigation is underway.