The shooting occurred around 2:10 a.m. in the area of New York Avenue and North Capitol Street, police Chief Cathy Lanier said.
Detectives were reviewing surveillance video showing gunshots being fired as two cars sped down the street in rapid succession, while a group of people on the sidewalk scattered and scrambled for cover. The police released the surveillance video to the public in hopes of gathering information on the gunmen. Police said shots came from at least one of the two cars.
The seriously wounded victim was shot in the back and was in critical condition Monday afternoon, police said. None of the other injuries was believed to be life-threatening, and the victims - who were either grazed by bullets or shot mostly in the legs, hands or other extremities - were reported to be conscious and breathing.
Police didn't immediately have a motive, and detectives were still interviewing witnesses and collecting bullet fragments and other evidence.
"We've got to interview a ton" of witnesses, said assistant police chief Peter Newsham.
The shooting occurred in the same area where multiple people were shot and wounded on consecutive weekends last October, though it wasn't immediately clear whether there was any connection.
Nor was it clear why the crowd was standing outside at that time of day, though Lanier said a club across the street had let out about 15 minutes earlier.
"Whether they came from the club, I'm not sure," Lanier said. "There is usually a pretty good crowd out here - Saturday night, Sunday night."