The Clue of the Left-Handed Envelope - George E. Stanley

Who sent an anonymous note to Amber Lee? The secret's in the spit! A new series from the pair that created Scaredy Cats, this time combining some of the most popular elements of kids' books--mystery, a classroom setting, and simple forensic science with a bit of gross-out factor. WHO SENT AMBER LEE AN ANONYMOUS LETTER? Everyone loves the new teacher, Mr. Merlin. Mr. Merlin used to be a spy, and he knows all about secret codes and the strange and gross ways the police solve mysteries. Now there's a mystery in their very own class -- someone sent Amber Lee Johnson an anonymous letter. Noelle and Todd want to solve the mystery before anyone else. But first they have to figure out Mr. Merlin's clues. How can a bunch of envelopes tell them who sent the letter?