A 15-year-old boy was killed and a police officer was among three others injured when someone opened fire in a crowd following an unpermitted music gathering in Washington, D.C., Sunday night, authorities said.

    The three surviving victims, including a Metropolitan Police Department officer, were stabilized at medical facilities, officials said at an evening press conference. The officer was shot in a leg, Chief Robert J. Contee III said.

    The attack was the work of one suspect, not in custody, who opened fire as police were clearly in the area, the chief said. He did not indicate that the officer was specifically targeted, only that it was a crowded situation on the street.

    The violence was reported near 14th and U streets Northwest, authorities said. It was near an event called Moechella, which celebrates  go-go, a genre of music that originated and is still popular in the District. 

    Earlier at the event, authorities said, something prompted people to flee, and some were injured, police said. Contee said the event was shut down at that point, but also indicated crowds remained in the area.

    Contee indicated police were patrolling the festival and its aftermath in abundant numbers — with more than 100 officers assigned to the area, he said.

    Moechella founder Justin Johnson, also known as Yaddiya, did not immediately respond to a request for comment. He's a noted artist, activist and go-go booster. Last year a photo book he helped curate, Long Live GoGo: The Movement, was published as a celebration of the percussive sound.

    The genre's most famous single, "Da Butt" by E.U. (Experience Unlimited), was featured in Spike Lee's second film, "School Daze," in 1988.

    The event is widely known in music circles and was mentioned in the city’s alternative weekly newspaper, City Paper, on Thursday. District of Columbia Housing Finance Agency (DCHFA), a federal entity, is featured on a Moechella flier as a supporter. A spokesperson for the agency did not immediately respond to a request for comment.

    In June, 2020 a D.C. councilman, Robert White, said he marched with Johnson during a Black Lives Matter demonstration, noting that the activist is leader of the group associated with Moechella, Long Live Go-Go.In 2018 the city's Department of Parks and Recreation boasted that it "hosted" a Moechella event it described as a "a festival filled with gardening activities, craft building workshops and live performances by local artists for students," according to a department performance report that included accomplishments and goals.

    It wasn't clear whether the unidentified teenager who died in the later shooting was targeted. The chief said crowded sidewalks and streets and too many guns create conditions for this kind of violence.

    "When things spill out into the street ...," he said, "that becomes a problem."

    He said multiple illegal guns were seized by officers in the area Sunday.

    Contee said police will look into the origins of the event and why it was allegedly able to take place without city approval. "We’ll be having those conversations with the office of the attorney general" of the District of Columbia, he said.

    Washington, D.C., Mayor Muriel Bowser appeared somewhat astonished at the brazen actions of the suspect with officers in the area.

"We have a child who was killed today at an event that did not have any proper planning for the number of people who were here," she said. 

    "We need some accountability," she said.