A Bed-Stuy man who fatally stabbed social justice advocate Ryan Carson in 2023 pleaded guilty to second-degree murder on Wednesday, prosecutors said.

Brian Dowling, 18 at the time of the killing, accepted a plea deal during a Jan. 22 hearing before Supreme Court Justice Danny Chun. The deal includes a sentence of 20 years to life in prison, which will be handed down on Feb. 19.

The fatal incident occurred on Oct. 2, 2023, at approximately 3:50 a.m. Carson, 32, was waiting at a bus stop on Malcolm X Boulevard and Lafayette Avenue with his girlfriend when they encountered Dowling.

According to prosecutors, Dowling, who was visibly agitated and kicking parked scooters, turned toward the couple, shouting threats, including, “I’m going to kill you.”

Carson, who worked with the New York Public Interest Research Group, attempted to deescalate the situation but was fatally stabbed during the confrontation. Surveillance footage presented as evidence showed Dowling swinging a knife at Carson, who tried to flee but tripped over a bench. Dowling ran up to Carson, stabbing him multiple times as he lay on the ground, striking his heart.

After the attack, Dowling discarded the knife but returned to retrieve it. A later search uncovered a knife, believed to be the murder weapon, hidden in greenery near the scene.

On Oct. 5, Dowling turned himself in at the 81st Precinct after being identified as a suspect. During a subsequent search of his apartment, investigators recovered multiple knives with handles resembling the weapon used in the attack and clothing matching those seen in the video footage, according to prosecutors.

“Many of us still shudder when recalling the horrific video showing this defendant viciously attacking Ryan Carson and stabbing him to death for no reason at all,” said District Attorney Eric Gonzalez in a statement. Such an unconscionable crime requires the separation of this defendant from our society for a very long time, which is ensured by the promised sentence he’s now facing.”

Gonzalez also acknowledged Carson’s commitment to social justice, noting that in 2021 he created the No OD NY campaign and lobbied for safe injection sites to combat overdoses.

“Ryan was passionate about making our city a better place and I hope that today’s outcome will bring his loved ones a small sense of closure,” Gonzalez added.