Incidents in at least four states — New York, Georgia, Florida, and Alabama — revealed a heightened level of vigilance in the days after the Feb. 14 school shooting in Parkland, Florida.

In Gainesville, Georgia, last Friday afternoon, a Hall County Schools bus driver heard a passenger say something about having a gun, according to the Hall County Sheriff’s Office. The driver alerted the transportation department via the radio, and the department called 911.

Deputies from the Hall County Sheriff’s Office and officers from the Gainesville Police Department responded to the scene. Authorities said they evacuated the bus and conducted a thorough search of the bus and the students, but they didn’t find any weapons The Hall County Sheriff’s Office said that investigators arrived and determined that “the incident was in fact a hoax perpetrated by a 16-year-old male student.” That student was arrested and charged with disorderly conduct, disrupting public operation of a school bus, and simple assault.

A similar incident took place in Daphne, Alabama, on Friday morning. According to Eddie Tyler, superintendent of Baldwin County Public Schools, “a student made flippant comments on a Daphne bus about bringing guns to school, another student heard it and called 911 from the bus.” Law enforcement officers responded to the scene and surrounded the bus. The superintendent didn’t provide further details on the incident, but he urged parents to impart to their kids the importance of not talking about guns or bringing guns to school.

None of us can go about our normal business after the Florida tragedy without giving serious introspection about the safety of our students,” Tyler said.

All school districts are on heightened alert to keep our students safe from harm on school buses, in school rooms and at school activities, with the copy cat incidents and threats that are currently happening,