The federal government (plaintiff) prosecuted Marcelino Guzman-Montanez (Guzman) (defendant) for possessing a firearm in a school zone, in violation of 18 U.S.C. § 922(q). A conviction required proof that Guzman was or had cause to be aware that he was within a school zone, which 18 U.S.C. § 921(a)(25) defined as an area within 1,000 feet of a public, parochial, or private school's grounds. The trial evidence showed that a police officer arrested Guzman, a suspect in an attempted robbery elsewhere in the city, at a fast-food restaurant located 300 feet from the gateway to a fenced campus. Guzman was armed at the time. Guzman did not live in the neighborhood. The government introduced no evidence to show that Guzman knew the neighborhood, ever drove by the school, could see the school's signage (if any) from the restaurant, or that the signage clearly identified the campus as belonging to a school. Guzman moved to dismiss the case for insufficiency of evidence. The jury convicted Guzman, and he appealed to the First Circuit Court of Appeals.