Police said the officer had reported a disorderly subject in a parking garage.
A 30-year-old man was arrested in connection with the incident, Laurel police said.
Davon Peyton, 27, of Alexandria, was arrested Saturday and charged with first-degree, police said.
Police said Shaquille Simmons, 24, of Northwest D.C., was found shot in Savannah Terrace.
No victim found in Shaw, but four apparently shot elsewhere.
Incidents occurred in prominent spots, and in at least two cases phones were taken.
One dog was fatally shot, police say; the second also died.
Witnesses told police that Jonathan L. Jones nearly struck a pedestrian with his vehicle, told the pedestrian it was an accident, and was shot.
Police say victim was hit while running down the lanes of I-270 in Montgomery County.
Jaquar McNair, 15, is the 10th child between the ages of 11 and 17 killed in the District this year.
Police arrested a 15-year-old girl in connection with the incident.
The incident occurred near Stadium-Armory Metro station.
Mamadou Bah, 22, was shot several times Friday night in the Adelphi area.
The victim was shot late Wednesday, the police say.
Defense attorneys had accused prosecutors of failing to turn over evidence, but a judge ruled there were no discovery violations.
Matthew Snell, 31, was taken into custody at the El Paso International Airport, police said.
Police assertions about the shootings stirred controversy among some black residents.
Henry K. Frese was working for the Defense Intelligence Agency.
Victims told police that shots were fired from a vehicle near Bryant and Second streets NW.