Bruce and the Mystery in the Marsh (Paperback, 2nd Title Change ed.)

When Chef Agatha learns that her mentor, Cecil, has died, she sets off to the marsh to pay her respects, and Bruce and Milton keep her company. When they arrive, however, Agatha discovers that Cecil didn't die of natural causes: he was murdered. Although Agatha must return home to teach her students, Bruce and Milton remain and are joined by Angie and Carly who help them search for clues. But as they get closer to learning the truth, they're threatened and later nearly killed. Determined to bring the culprit to justice, they continue their search, but will they learn the identity of the killer before he (or she) can strike again?