Police charged Randy Aaron Powell, 17, with first-degree murder for the killing of Marvin Alexander Mendoza.
Another suspect – 19-year-old Erik Aguilar of Silver Spring – was arrested last week on the same charge.
Just before 9 a.m. on Tuesday, August 10, emergency officials received a call about a shooting in the 2000 block of Blueridge Avenue. Several officers responded and found Mendoza dead from a gunshot wound.
The chaos caused a shelter-in-place order to go into effect for students and staff at Arcola Elementary School and Odessa Shannon Middle School.
Police initially said "four suspects" were seen running from the scene.
They have not indicated what may have led to the shooting.