A person cannot give law enforcement permission to search their roommates bedroom (unless it is shared), a bedroom is an area where a person has a reasonable expectation of privacy if it is not shared. If a person lives with another person (and they are not married) and the police wish to search the residence when only one of them are present the police (unless they have a warrant) can only search the common areas like the livingroom, kitchen and bathroom. While searching the common areas only items in plain sight can be taken and used as evidence, if something is in a drawer or behind a closed door it is not admissible. Anything Knight and Torres find in Arthur Vernon's room would be inadmissible as evidence, they did not have permission from the room's occupant, nor probable cause, and the items they found were not in plain sight.