UPDATE:
Alexandria Shooting: Suspect Is One of Two Dead
"The suspect, identified as Yerson Nunez Lopez, 19, of Maryland, and the 17-year-old girl died on the scene. The 15-year-old boy went to the hospital with serious injuries and is in stable condition. Alexandria Police do not believe the incident is gang-related and say the suspect and victims knew each other. The name of the girl has not been released."
https://patch.com/virginia/oldtownalexandria/alexandria-shooting-suspect-one-two-dead