When the officer is done taking the finger prints of Mr Lampe, the camera shows Mr Lampe's palm and fingers covered in black ink. The next scene, Mr Lampe is using a white cloth to clean his hands. There is no black ink on the white cloth from wiping his hands and both of Mr Lampe's hands are spotless (no ink).
When the apartment manager is at the door and starts telling Friday and Gannon who he is, and details of the crime scene, he asks for their badges/ID's. Neither Friday or Gannon ask the manager for his ID.