CHATFIELD, Minn. – A 14-year-old boy out on his own on a three-wheeler was seriously injured when the vehicle crashed. The boy, Marick Mercer, was airlifted 20 miles to a Rochester hospital. Immediately he underwent two operations. The injuries were inside the chest cavity. Serious too were multiple skull fractures and ongoing brain swelling. His father, Keith Mercer, found the boy unresponsive when he returned home three miles northwest of Chatfield about 1 p.m. This was near the 12700 block of Mill Creek Road Southeast.