A shard of glass with a fingerprint on it is recovered at the crime scene of the theft of the Pink Panther diamond. Clueless, Clouseau takes the shard and discards it much to the dismay of the other detectives. However, the real thief would never have made such a mistake, therefore it had to be a plant.
More likely, the fingerprint was actually Clouseau's (or the fingerprint of his night guard friend) since they were the ones who actually stole the diamond to keep it safe. If they had identified the print on the glass, Clouseau would have become a suspect and the police would have found the real Pink Panther in his home!
