At least four people were killed and another 25 were injured as a bus plunged into a ditch on the Dhaka-Rangpur highway under Pirganj upazila in Rangpur district on Monday.The identities of the deceased could not be identified yet.Officer-in-charge of Pirganj Police Station Rezaul Karim said the Rangpur town-bound bus from Dhaka fell into the ditch at Madarpur around 9:15 am after breaking the railing of a bridge as its driver lost control over the steering, leaving two passengers dead on the spot and 27 others injured.Of the injured, 15 were taken to Rangpur Medical College Hospital where doctors declared two of them dead.The bodies were sent to the hospital morgue for autopsy.