Photo: Rarrarorro/Getty

national-mall-washington-monument

A 15-year-old boy was killed and three people — including a police officer — were wounded after a shooting at a street concert in Washington, D.C. on Sunday evening.

Police tellCNNthat several hundred people had gathered to hear music performed in the back of a truck on a D.C. street. According to theThe Washington Post, the concert was advertised under the name Moechella, a name intended to protest alleged suppression of go-go music in the Black community. The concert was set to run from 4 to 8 p.m.

As the crowd grew and police perceived the conditions to be unsafe, officers arrived on the scene to shut down the concert. In a news briefing on Sunday, D.C. Police Chief Robert J. Contee III said that there had been two previous incidents before the shooting.

Shortly after the crowd dispersed, gunfire erupted, killing the teen and injuring three adults. Police seized several firearms at the scene.

Want to keep up with the latest crime coverage? Sign up forPEOPLE’s free True Crime newsletterfor breaking crime news, ongoing trial coverage and details of intriguing unsolved cases.

All three adults were hospitalized in stable condition, CNN reports. None of the victims have been identified.

At the press briefing, D.C. Mayor Muriel Bowser expressed sadness and frustration at the teen’s death.

“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 and with guns involved,” Bowser told reporters. “The chief and I will continue to make sure we have the resources we need on these corridors and all of our corridors but we need some accountability here.”

According toNBC News, police believe that the attack was the work of one person who opened fire. The suspect has not been named and is not currently in custody.

source: people.com