Nope, not as long as they are performing their official duties. You cannot record anybody in private, such as a restroom. The standard on recording anybody is a reasonable expectation of privacy. North Carolina is a one party state when it comes to recordings over a telephone, or private conversations. If you record a police officer in a private conversation without consent or knowledge then you are breaking the law.
While the police officer does not have a reasonable expectation of privacy while performing duties, the civilian population that the officer is interacting with does. So you could still be charged if you are not one of the parties in the conversation.