Arrest Made in Fatal Stabbing of Advocate in Brooklyn

A person was in custody on Thursday morning in connection with the fatal stabbing earlier this week of an activist in Brooklyn, a spokesman for the New York City Police Department said.

The victim, Ryan Carson, 32, was stabbed repeatedly shortly before 4 a.m. on Monday morning in Bedford-Stuyvesant, the police said. When officers arrived, they found Mr. Carson lying on the sidewalk, unresponsive, with stab wounds to his chest. He was taken to Kings County Hospital, where he died.

Video footage of the killing showed Mr. Carson being attacked by a man who had walked past him and his girlfriend on the street seconds earlier. The man appeared agitated and had begun knocking over scooters on the sidewalk before the couple walked toward him.

The Police Department spokesman said no further information about the person in custody was available on Thursday morning. A spokesman for the Brooklyn District Attorney’s office said he had no information about the case.

Mr. Carson, who worked at the New York Public Interest Research Group, was well known in Brooklyn political and activist circles, and his killing on Monday was met with an outpouring of grief from elected officials and advocacy groups.

“Ryan Carson threw himself into everything he did with passion and humanity,” Senator Chuck Schumer of New York, a Brooklyn resident and the Senate majority leader, wrote on X, the platform formerly known as Twitter.

“I worked with him on a big town hall he hosted with NYPIRG and on the Inflation Reduction Act,” Mr. Schumer wrote. “A rising talent and an extraordinary activist. May his memory and work inspire us.”

Through video and witness interviews, detectives determined that Mr. Carson and his girlfriend were sitting on a bus stop bench at 3:47 a.m. when a man walked by, Joseph E. Kenny, the Police Department’s chief of detectives, said at a news conference on Wednesday.

At first, the man and the couple did not interact, Chief Kenny said.

However, after the man had walked about 40 feet away, he stopped and began kicking and damaging mopeds parked on the sidewalk. The couple stood up and began walking toward him, Chief Kenny said. Suddenly, the man turned toward the couple and asked Mr. Carson, “What are you looking at?”

“Mr. Carson immediately tries to de-escalate the situation,” Chief Kenny said. “This male then produces a knife and swings it at Mr. Carson, who begins to back up. Mr. Carson eventually trips and falls to the ground. The unidentified male then stabs Mr. Carson three times, striking him once in the right chest.”

One of the stab wounds pierced Mr. Carson’s heart, the police said, causing his death.

As Mr. Carson lay on the sidewalk, the man stayed briefly at the scene, kicking him and threatening the woman, Chief Kenny said. Shortly after, a woman — who appeared to know the assailant — appeared at the scene, apologizing to the couple and calling the attacker by a name, he said.

Before the stabbing, the attacker was seen on the corner with the woman, who the police believe to be his girlfriend, “acting very agitated,” Chief Kenny said.

A vigil held for Mr. Carson in Brooklyn on Monday evening drew a crowd of more than 100 people, according to reports. An online fund-raiser for his family had collected nearly $65,000 as of Thursday.

Local leaders hailed Mr. Carson’s work as an activist. Jumaane Williams, the New York City public advocate, described him as “a friend, mentor and ally” and said he was “devastated” by the killing.

“I’m horrified to learn of the brutal murder of advocate Ryan Carson in Brooklyn today,” Chi Ossé, a city councilman who represents Bedford-Stuyvesant and Crown Heights, said on X. “This tireless defender of his neighbors was stolen from us.”