The Case of the Stinky Socks — Lewis B. Montgomery

The Milo & Jazz Mysteries stars two kid detectives-in-training who use STEM problem-solving skills as they race to unravel cases and save the day! Perfect for fans of Encyclopedia Brown, Cam Jansen and Nate the Great.
 
The high school's star pitcher is missing his lucky socks, and his pitching is going to pieces! Can detective duo Milo and Jazz find the thief -- before the big game? 

The Milo & Jazz Mysteries is an ideal series for beginning readers making the transition to chapter books. It also features “Super Sleuthing” activities in each book, including hidden pictures, puzzles, mini-mysteries, and quizzes -- plus free online activities.