A 16-year-old boy died Wednesday after suffering an injury at Codman Academy Charter Public School in Dorchester earlier in the day, Boston police said. Officers responded to the school at 637 Washington St. around 3:35 p.m. after receiving a call for someone in cardiac arrest, police said. Officers found the youth suffering from a life-threatening injury, the statement said, and he was taken to Children’s Hospital Boston, where he was later pronounced dead. The statement did not detail the nature of the boy’s injury, and a police spokeswoman declined further comment. School officials also declined to comment Wednesday.