D.C. officials pleaded for public help Sunday evening in finding the person who fatally shot ­16-year-old Breyona McMillian, a student who was visiting family for Thanksgiving when she was gunned down Friday.

Police say McMillian was the unintended target of gunfire when a large group gathered in the 1200 block of I Street SE, near Capitol Hill, on Friday morning.

“It appears at least one suspect fired multiple times indiscriminately, and as a result of that reckless behavior, we lost one of our 16-year-old kids,” said interim D.C. police chief Peter Newsham.

Newsham joined Mayor Muriel E. Bowser (D) in a Sunday evening news conference, decrying a rash of violence that has left three dead in the city since Friday morning.

“It is so important that we hear from you so that we can get a brutal killer off of our streets,” Bowser said of McMillian’s killing.

The other two shootings, which were not believed to be related, occurred Sunday afternoon. Just before 1 p.m., Anthony Young, 27, was fatally shot and a woman was wounded in the 600 block of L Street SE, in the Navy Yard neighborhood. Police said Young and the assailant knew each other.

Hours later, another man was killed in a shooting in the 1300 block of Howard Road SE. He had yet to be identified Sunday night.

Newsham said that while “significant” evidence has been recovered from each scene, suspects had yet to be identified.

City officials hope witnesses will step forward and urged public cooperation in McMillian’s case.

“We’re asking because we know many people were near the scene,” Bowser said.

Newsham said he was hopeful more information will emerge.

“When you lose a kid like this in our community, I think that touches us all,” he said.