The Swimming Pool Mystery — Martin Widmark

Jerry and Maya, classmates and best friends, are on the case again and ready to solve the latest caper in this international bestselling series!
 
It's Christmastime in Pleasant Valley and the town is getting ready to celebrate. But when all the lockers at the Pleasant Valley swimming pool are emptied during the Big Holiday Swim, it looks like Christmas won't be very merry. Once again, Jerry and Maya use their super sleuthing skills to help the police chief track down the mysterious thief before he ruins Christmas for the whole town!