The Frog Who Croaked (Platypus Police Squad Series #1)

Platypus Police Squad: The Frog Who Croaked is the first in a series of zany, action-packed middle-grade mysteries featuring platypus police detectives Rick Zengo and Corey O’Malley.
 
When a call comes in about a crime down at the docks involving a missing schoolteacher and a duffle bag full of illegal fish, Zengo and O’Malley are going to have to learn to set their differences aside if they want to get to the bottom of this. Especially when the clues all point to Frank Pandin…