US v. Roe: Roe was a privately contracted security guard working at a NASA facility in Maryland. Roe possessed a Maryland handgun permit and state certifications for being a private security guard and private detective. As part of his job, he had the limited authority to arrest and otherwise provide law enforcement services on NASA grounds. He was pulled over on the highway in a car done up to look like an unmarked police car after some interactions with a Maryland state police officer (in a real unmarked car). When he got out of the car, he told the arresting officer "I'm the police! I'm the police" and that he was a federal police officer. He produced a badge that had "NASA" and "police" on it, which the officer recognized as inauthentic. Roe was charged with impersonating an officer of the United States. At trial, the Government produced testimony from a Maryland state police officer who testified that the state certifications Roe possessed did not give him arrest authority under state law or turn him into a police officer. Roe was convicted and sentenced to probation.
On appeal, Roe raised three arguments seeking to overturn his conviction, each of which the Fourth Circuit rejected. First, he argued that the district court erred by allowing the state police officer to testify about Roe's certifications and their effect because he was not qualified to testify as an expert witness. The court disagreed, holding that the officer's testimony was lay testimony, not expert, and he could testify about the permits because of his position in the office that issued such permits. Second, Roe argued that the evidence was not sufficient to convict him, particularly given that he was, in fact, employed as a "security police officer" at NASA. In other words, he could not impersonate a federal officer because he was one. The court disagreed, holding that the statute reached situations where the a person claimed to be a federal officer in a situation in which they were not acting as such (i.e., posing as an officer beyond the scope of their actual authority). Finally, the court rejected Roe's argument that the district court's instruction using the term "police officer" instead of simply "officer" was an impermissible amendment to the indictment.
Judge Gregory dissented from the court's conclusion with regards to the sufficiency of the evidence. He argued that the language of the statute was clear and that liability applies only to those who are not at all federal officers and claim to be. When he stated "I'm the police!", he was likely "attempting not to get shot by identifying himself as one of the 'good guys,'" rather than trying to actually mislead anyone.