RAPID CITY, S.D. (AP) — A teenager is in custody for allegedly bringing a BB gun that resembled a handgun onto school property in Rapid City.

Police say Rapid City High School was put on lockdown about midday Monday when the 18-year-old male was seen with the gun in the school's parking lot.

Officers tracked him down a few minutes later and arrested him on misdemeanor charges of possessing a weapon on school grounds and disturbing a school. They say he had the gun tucked in his waistband.

Authorities say the teen is a student at Central High School, and they're still investigating why he was at Rapid City High.

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