In 2016-2017, no one was caught with a weapon at Great Mills High School in St. Mary’s County, Maryland, where 17-year-old Austin Wyatt Rollins shot two other students, injuring one critically, before being shot and killed by a school resource officer.

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There were just nine weapons found in all of St. Mary’s County Schools in 2016-2017, according to data on the Maryland Public Schools website.

That’s a fraction of what turns up in bigger counties. In Prince George's County Schools 413 weapons were found, 179 were found in Montgomery County schools over the same time period.

Bringing a gun onto school grounds is only a misdemeanor but for a first time offender it carries a minimum 30-day prison sentence and maximum 3-year sentence. The fine can be as much as $2,500.

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The law does not apply to on duty police officers or off duty law enforcement provided they are carrying their badge and their gun is concealed.

Maryland also has some educational exceptions to the school gun ban including historical demonstrations using a gun or replica weapon, or an organized shooting activity for educational purposes.

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But the principal has to sign off on those demonstrations with a written invitation to bring those types of guns onto school grounds.