A 13-year-old school boy was mowed down by a speeding Blueline bus in the capital on Thursday morning, making him the 107th victim of the notorious killer fleet.Nakul, Class VIII student of Balak Ram Higher Secondary School, came under the wheels of the bus at Wazirabad at around 8 am, police said.He was rushed to Sushrut Trauma Centre where he succumbed to injuries.The driver of the bus, Ram Singh, was arrested, police said.