Karon Brown, 11, from last year, playing defensive end for the Woodland Tigers football team. (Michael Zanders, director of the Woodland Tigers Youth Sports and Educational Program)

A suspect has been arrested in connection with the shooting death Thursday of 11-year-old Karon Brown, police announced Saturday.

D.C. Police Chief Peter Newsham said a motive in the killing of the boy still was not known. At a news conference at Naylor and Good Hope roads SE, near the site of the shooting, Newsham said Tony Antoine McClam, 29, of Southeast was arrested Saturday and charged with second-degree murder.

It was unclear whether the boy was targeted, Newsham said.

“I am happy they got him,” the boy’s mother, Kathren Brown, said Saturday. “But honestly, it doesn’t bring my son back.”

It was not clear what led police to the suspect. However, D.C. Mayor Muriel E. Bowser (D) said members of the community had “put their outrage into action.”

She and Newsham decried the presence of illegal guns on the streets. There was “absolutely no reason in the world why we should be burying an 11-year-old boy because some adult thought it was okay to discharge a firearm in our community,” the chief said.

After the shooting, police had published images of a suspected shooter, a man in his late 20s or early 30s, running shirtless and clutching a handgun. They said as many as five people were being sought in the incident.

Bowser went to the scene Thursday to urge residents to help police find the people involved “so we can take the killer off the streets.”

She later said federal law enforcement pitched in to double the city’s standard reward in a homicide case to $50,000.

Karon and his brother Quentin, 12, had walked Thursday evening to the McDonald’s not far from their home to get food for their older sister. Quentin became impatient and returned home, but Karon stayed.

Quentin was sent back about 7 p.m. to get his brother, but by that time, a fight inside the restaurant involving children and adults had spilled into the street.

Quentin heard gunshots and raced home. His little brother never made it back.

Amid the fighting, authorities think, a passerby saw Karon being assaulted and tried to help him by beckoning him into his car. But as the driver tried to get the boy to safety, someone in the crowd fired a shot that entered the vehicle, striking the boy.

Weeks before he was to begin sixth grade, Karon died at a hospital.

The series of events was described Friday by police officials who spoke on the condition of anonymity to discuss an open investigation. At that point, they said, they thought the gunman targeted the boy. But both the circumstances of the shooting and the fight have remained unclear.

“I just lost it. I couldn’t believe it,” the boy’s mother said Friday.

“I still can’t believe it. I am waiting for someone to say all this did not just happen,” she said. “This is not how we planned our summer. Now I have to sit here and plan a funeral for my baby.”

Karon’s killing comes amid concern over an uptick in deadly violence in the District.

Brown said she and her family had moved about a year ago to Woodland Terrace, a public housing community about a half-mile from where Karon was shot. Brown said she was trying to escape violence in her former Northeast neighborhood.

They had lived near Makiyah Wilson, a 10-year-old girl who was shot and killed last year, an unintended victim, police said, of a feud between neighborhood crews. Makiyah, Karon and Quentin were all friends and attended school together, Brown said.