Chet Gecko, Private Eye Volume 1: The Chameleon Wore Chartreuse; The Mystery of Mr. Nice

Listen to the first two hilariously hip Chet Gecko mysteries in this one audio download!
 
The Chameleon Wore Chartreuse: Chet Gecko loves a good mystery. Almost more than he loves his fee—stinkbug pie. So when fellow fourth grader Shirley Chameleon asks him to find her missing brother, Billy, Chet expects the case to be as easy as pie. But Billy's disappearance is part of a larger plot, one that involves the Rat Sisters, a riddling junkyard dog, and a vicious Gila monster named Herman. If Chet doesn't solve the case fast, the entire school could be humiliated. Worst of all, Chet might not get his fee. And Chet's hungry. . . .
 
The Mystery of Mr. Nice: Most folks know him as the best lizard detective at Emerson Hicky Elementary, but it's not all knuckles and know-how with Chet Gecko. He's also got his artistic side.  If it wasn't for his art, he might never have been sent to Principal Zero's office, where he stumbled onto the mystery of Mr. Nice. Because whatever you can say about Principal Zero, one thing is certain: He is not nice. Until now. Chet knows something is wrong with this picture, and he's just the gecko to solve this mystery. After all, who do you think put the art in smart aleck?