Four people were killed and about 25 passengers injured as a bus rammed into a container truck on the Yamuna Expressway in Uttar Pradesh’s Mathura district early on Tuesday, police said.Senior Superintendent of Police Shlok Kumar said the accident took place around 4 am when the bus was coming from Lucknow.”Preliminary investigation and statements of the injured passengers indicate that the driver was not driving the bus at the time of the accident. Instead, the conductor was behind the wheel and was driving at a high speed,” Kumar said.He said the container was travelling in its designated lane when the speeding bus suddenly swerved and crashed into it from behind.A detailed investigation has been ordered to ascertain the exact circumstances leading to the accident, the SSP said.The deceased have been identified as the bus driver, the conductor, the cleaner and one passenger.The injured were admitted to the district hospital, where District Magistrate Chandra Prakash Singh and SSP Shlok Kumar met them.Police and district administration officials are supervising the treatment of the injured, while arrangements are being made to ensure their safe onward journey, Kumar said.He said the families of all the passengers had been informed.”None of the injured is in a critical condition. Two of them have suffered fractures and are being provided the best possible treatment,” the SSP said.