Who Stole Uncle Sam? — Martha Freeman

Two eleven-year-old sleuths crack a case about the disappearance of a baseball coach in this humourous and offbeat middle-grade mystery, third in Martha Freeman's popular series. After their last success, Alex and Yasmeen made a pact to stop solving mysteries. However, when Alex's baseball coach, a patriotic war veteran nicknamed Uncle Sam, goes missing, it's hard for the young detectives to resist. Soon the two are tracking down clues involving porta-potties, lawn care chemicals, and secret baseball scouts. Will Alex and Yasmeen get to the bottom of the mystery before the summer is over?