- A funny and exciting picture book about a brave police officer and his clever dog. (And about a surprise party. Shhh!) For keen noses ages 4 and up. Police Officer Pete has an important job today. The chief asked him to take a letter to the post office. It says TOP SECRET in big black letters. Pete immediately sets off, but then someone steals his cap. "Stop, thief!" Officer Pete calls. And he sets off in pursuit with his tracking dog, Sniffer. Will Pete find his police cap? And who's the thief?