Gunman Is Arrested in Brownsville Mass Shooting, Police Say

A gunman who opened fire on a rival at a neighborhood block party in Brooklyn, killing one and injuring 11 others, was arrested late Wednesday, the police said.

The man, Kyle Williams, 20, was taken into custody on murder and other charges in connection with the July 27 mass shooting that turned the Brownsville Old Timers Day block party into a blood bath.

Mr. Williams lived about a half-mile from the Brownsville Playground, where police said he shot and killed Jason Pagan, 38, before turning the gun on a dispersing crowd. The wounded victims, who ranged in age from 21 to 55, were struck in the back, legs and head as they fled.

Shell casings from the scene indicated that two shooters exchanged gunfire during the episode, the police said.

In addition to murder, Mr. Williams also faces charges of attempted murder, reckless endangerment and criminal possession of a weapon. He was expected to be formally charged on Thursday in criminal court in Brooklyn. It was not immediately clear if he had a lawyer. Mr. Williams had no prior criminal history, the police said.

In a Twitter post, Dermot F. Shea, the chief of detectives, said the arrest followed “an extensive investigation.”

The police did not immediately offer a motive for the shooting, but officials have described it as a gang dispute. Mr. Pagan was a Bloods gang member who was released from prison six months before he was killed, the police said.

Partygoers had been singing the O’Jays’ “Family Reunion” at the annual homecoming event before the shooting started.

The episode jolted a city where crime has declined, but where gunplay between rival gangs has wounded or killed more than a dozen bystanders since June, the police have said. It was the first instance of violence at the event in its 56-year history.

Mayor Bill de Blasio drew criticism from his fellow Democrats in Brooklyn for initially refusing to label the crime a mass shooting. He later capitulated to local officials and community leaders who said the designation was important to draw empathy and resources to a neighborhood that has made strides in reducing crime but still needs help.

Mr. Williams was one of at least two men that the police were seeking in connection with the shooting.

The police did not immediately say how they found Mr. Williams. His arrest came two weeks after the police increased the reward for tips to $20,000, and released photos and video of two women wanted for questioning in connection to the shooting.