In the intro crime, right before the opening theme, a woman is seen repeatedly stabbing a man. However, in each "between stabbings" weapon close-up, there is no blood at all on the knife.
Rebecca exits her cell wearing the sunglasses her manager Marty just put on her nose. She turns around to look at Nick Knight who remained in the cell: at that moment she isn't wearing the sunglasses yet she didn't remove them.
Nick calls Schanke from the crime scene to ask him to take the Polaroids to the lab. But in the previous scene in his apartment, Nick took out the Polaroids from his coat pocket right before heading to the crime scene: those Polaroids are still in Nick's possession.