The Falcon's Malteser - Anthony Horowitz

Tim Diamond is possibly the world's worst detective. He's dense, he's distracted, he's unbelievably dim-it's a good thing his younger brother Nick is around! Nick knows there'll be trouble when Tim's entrusted with a package worth over five million dollars, but he doesn't know how much trouble. When the owner of the package is murdered, Tim gets the blame, Nick gets the package, and every crook in town is out to get them! Can Nick outwit them and turn this candy caper into a sweet deal for the Diamond Brothers?
Full of humor and non-stop action, this mystery series by the author of Stormbreaker will leave readers eagerly awaiting more.