All passengers got off the bus safe and well and the fire service attended to extinguish the fire.
It is believed the suspect got on the bus on Bridge Street, St Helens and got off on Warrington Road, before going in the direction of Martin Close.
Detective Inspector Tony O’Brien said: “Starting a fire on a moving bus is an utterly irresponsible act and it is very fortunate that no one was harmed by the actions of the suspect.”
Anyone with information should call 101, DM @MerPolCC or contact @CrimestoppersUK anonymously on 0800 555 111 with reference 20000059685.
