Police have charged three juveniles with arson and breaking and entering in fires set inside a former Woonsocket school. The Police Department responded Thursday to 357 Park Place, the former Woonsocket Middle School, after an alarm went off. Authorities said three juveniles were seen running from the school and one was found injured nearby. The injured boy told officers he hurt his ankle jumping off the fire escape. Police found several fires smoldering in the bathroom areas. The juveniles who fled were found, and each was charged with breaking and entering, second-degree arson, vandalism, and two counts of conspiracy, police said.