Three motorcycle riders were killed when a bus hit the head of a motorcycle carrying them in Rajshahi city at Friday night.The incident took place in front of the liberation war memorandum stadium around 11 pm.The deceased were identified as Bachhu, 35, engine mechanic of truck of Malda Colony of the city, his assistant Ershad, 25, and Adu, 45.Locals rushed them to Rajshahi Medical College and Hospital (RMCH) where attending doctors declared them dead.Shahadat Hossain, officer-in-charge of Boalia Model Police Station, confirmed the incident.