The Diamond Brothers in The Falcon's Malteser by Anthony Horowitz
Meet the Diamond Brothers, the world's worst private-detective agency, in this Chandler-esque spoof from the creator of the Alex Rider series. When a dwarf comes into the office and leaves a package, Tim Diamond, the world's worst private-detective, is faced with his toughest case yet. The office is ransacked and the package is found to contain simply a box of Maltesers. Who was the dwarf ... and why was he murdered shortly after his visit?