We have had situations like that here too. Anyone can buy a light bar from ebay or something and get themselves a uniform and fake badge.
Running a blue/red light here, and not being a cop on duty, in a police car, is illegal. Undercover cops can only use a red light. Using a red light as a firefighter/emt/medic/nurse/cop/garbage man/whatever, needs to be licensed from the state which needs approval from the chief of operations from whomever you are responding for. Same goes with use of a blue light. None of them can be used, unless there is an emergency, and illegal if used when there is not one. (except for on private property or something for showing off).
If you are a volunteer and have a blue light, they must be taken off or covered up when you cross state lines, such as NY or VA. Since in those states, those colors are reserved for police vehicles.