Marcus King, the 19-year-old sought in a fatal shooting of a recent American University graduate in Shaw, surrendered to D.C. police early Friday, according to the department’s spokeswoman and the police chief. (WUSA9)

Matthew Shlonsky, on his way to a Saturday afternoon gathering with friends, stepped out of a taxi at the Metro station in Shaw and into a neighborhood feud between rival crews that had been largely dormant for years.

As the 23-year-old turned to walk up Seventh Street NW, witnesses told police, two men pulled black and silver handguns from their waistbands. “Watch out!” one of the gunmen yelled. “Get out of the way!” screamed the other.

Eight shots. Then nine. Most, if not all, police said, were aimed at a burgundy Chrysler driven by a man waving a gun through the sunroof. Shlonsky, a financial analyst and a 2014 American University graduate, was struck once in the chest and collapsed on the sidewalk outside a muffin bakery. Police said he was not the intended target.

New details in the Aug. 15 shooting at the Shaw-Howard University Metro station at Seventh and S streets NW came Friday with the surrender of 19-year-old Marcus King, who lives with his mother at the Heritage Shaw Station apartments, one block from the Metro. He was charged with second-degree murder.

Marcus King (D.C. Police)

The arrest affidavit says that King admitted to firing two guns — a .22-caliber and a .40-caliber — but said that the gunman in the Chrysler shot first. He told police that he fired two or three times, “at the most,” and threw the .40-caliber gun in a trash can at a barbershop. Police said they found the Chrysler on Monday in Northeast. It had bullet holes, police said, and inside were pellets and a CO 2 cartridge often used in air guns.

In a brief interview, King’s mother, Diane King, said: “My son is innocent. They shot at my son first. He is nothing but a victim.”

King’s attorney, Brandi Harden, argued at an initial appearance in D.C. Superior Court on Friday that there was no evidence bullets fired from the .40-caliber weapon that her client admitted firing had killed Shlonsky. She said that a more appropriate charge would be manslaughter.

But Assistant U.S. Attorney Shana Fulton called the eruption of gunfire an “urban-warfare shootout.”

Police said that 18 shell casings were scattered on the sidewalk and grass and that evidence showed guns were fired on two corners at Seventh and S streets. Police have not said whether shots were fired from the Chrysler.

“This was a shootout, and it was reckless,” Fulton said.

A judge ordered King detained until his next hearing, on Sept. 23. Police are still looking for at least five more people in Shlonsky’s shooting.

One of Shlonsky’s friends, 25-year-old Ben Metak, said he was pleased with the arrest but wants to learn the definitive motive. “I’m happy the police are making progress,” said Metak, who was walking toward the Metro when his friend was shot and arrived to see police giving Shlonsky first aid.

“It feels good to get a little bit of good news after a hard week,” he added.

Police have not revealed a motive for the shootout but raised the possibility of a dispute over a dice game. Court records say that earlier Saturday, King had argued with a young woman he thought was from the rival 7th and O street crew but, in fact, lived in Northeast. That woman had threatened to get her uncle “to take care of him.”

King’s arrest is the first publicized break for police amid a surge in violence that has pushed the District’s homicide count to 99 for the year — a 35 percent increase from the same period last year.

There have been three fatal shootings in Shaw this year, compared with none in all of 2014. One killed longtime resident and activist Tamara Gliss, who police say was struck by a stray bullet fired into a crowd at a Memorial Day cookout at Seventh and O streets.

Authorities believe that Gliss’s shooting was not a result of the violence between rival crews linked to the latest shootings, which officials believe are connected. But a member of the D.C. Council and a member of the Advisory Neighborhood Commission, who have been briefed on the police investigation, said the Aug. 15 shooting at the Metro is connected to a shooting on Aug. 11 that wounded three people and to a shooting Aug. 8, in which King was shot through the neck in front of his apartment.

In the arrest affidavit, D.C. police said that King is a member of the 8th and R street crew, which feuds with the 7th and O street crew just a fejw blocks away. They are two of three rival gangs in Shaw that police and residents say are responsible for decades of violence in the neighborhood and had entered into a truce in 2007 that activists say remained largely intact until this summer.

“It is unfortunate that this current generation has tried to take up arms again and revisit perceived slights that go back so many years,” said Alexander Padro, an ANC member in Shaw. “Only time will tell whether or not there is an end to this.”

Padro said that violence among the crews “had been down to a dull roar for a long time.” Of Shlonsky, he said, “It’s devastating that this innocent victim had to lose his life because these young people have decided to address their disagreements with gunfire.”

Authorities said that $3 billion in private and public investment has poured into Shaw in the past decade, helping turn one of the District’s most historic neighborhoods into a target for revitalization and a destination for newcomers and their families. Across the street from where King lives is City Market, luxury apartments above upscale food stalls advertising “convenience for an entirely new urban market experience.”

“It’s very frustrating to see folks who have come to live in this neighborhood, believing it was safe, and having to worry about whether or not they can bring their kids to school,” Padro said.

But Tyrone Parker, director of the Alliance of Concerned Men, which brokered the 2007 truce, said little has changed for the longtime residents. They complain about feeling locked out of the new jobs and unwelcome at the recreation center.

“Some of the shooting is in-house,” Parker said, meaning inside Shaw. “Some of this is beefing with outsiders.” Parker said he met with a group of teenagers at a Starbucks earlier this week and was joined by a top D.C. police official. He said the youths told them, “We’ll turn in our guns for jobs.”

After the triple shooting on Aug. 11, D.C. police flooded Shaw with officers on foot and erected a tent staffed continuously with police at Seventh and O streets to help residents both feel at ease and have someone to talk to. The Aug. 15 shooting at the Metro was four blocks away.

Padro said the deployment “has satisfied the immediate concerns” of the community. But, he added, “we’re concerned about long-term sustainability.”