Steven Alston Jr., a junior, shot the tenth-grade victim around 1 p.m. in a bathroom at the Muncaster Mill Road school in Rockville, Montgomery County police said.
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The victim was rushed to an area hospital and was reportedly in serious condition.
The school went into a full lockdown at 1:05 p.m., bringing local police and a SWAT team to the scene.
Alston was found in a classroom and arrested around 3 p.m., police said. A privately manufactured firearm (ghost gun) was found inside the school, which is believed to be the gun used by Alston, authorities said.
Alston was charged as an adult with Attempted 2nd Degree Murder, 1st Degree Assault, Use of a Firearm in the Commission of a Felony/Violent Crime, Possession of a Dangerous Weapon on School Property, and Possession of a Firearm by a Minor.
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