Frog and Wombat (1998)

From her bedroom window, Alli (code name "Frog") thinks that she has discovered the cover up of a serious crime. She is convinced that her new school principal has committed a murder, and she is going to prove it! When her best friend, Jane (code name "Wombat"), rejects this idea, a brazen Frog decides to set up surveillance, collect some evidence and break the case.