Have you checked the back room of the funereal parlor yet? Mr. Kauffman will permit you to search it. There is a load of evidence there , including a body bag in the garbage pail. Swab it. Also take a piece of the plastic with the tweezers and compare it with the one you took from the cactus at the circus. You'll find that they match.
Oh, and have you gone to the Coroner's yet and swabbed the insides of the lizard? Very important! You'll receive two set's of DNA...