Everything we know about Brooklyn teen accused of killing social justice advocate Ryan Carson

The accused killer of rising public policy advocate Ryan Carson was arrested Wednesday and charged with murder as more details about the troubled Brooklyn teen suspect came to light.

Brian Dowling, 18, was taken into custody at his Bedford-Stuyvesant home steps from Malcolm X Blvd. and Lafayette Ave., where days earlier he fatally stabbed Carson, 32, while the victim’s terrified girlfriend watched, police said.

In the caught-on-camera slaying, a woman police sources revealed is Dowling’s sister apologized to the couple as Carson lay dying on the sidewalk.

When officers banged on Dowling’s door Wednesday morning with no answer, they took the door down and made the arrest, sources said.

During the three-day search, the teen moved around, staying with friends as he evaded arrest. He made no statements to police after he was nabbed and quickly asked for legal representation, instead.

Outside Dowling’s family’s home Wednesday afternoon, his father, identified by a friend as Brian Dowling Sr., was reeling.

“I’m just a guy,” the older Dowling said. “I’m going through it.”

The teenaged Dowling lived with his parents and twin sister in a multi-generational home once owned by his late grandparents, according to a close family friend.

“Just like any other teenager,” Eric Riddick said of the accused killer. “(He’s) just a young teenager finding his way, coming up as an adult. It’s a horrible situation for everyone.”

The teen recently graduated from high school and was working multiple jobs while his twin sister was headed to college.

“He was into sports,” Riddick said. “I went to some of his basketball games. He was all right. I kinda saw the basketball thing fade away maybe his junior year.”

Most recently, Dowling was working in construction, said Riddick, whose relationship with the family dates back decades.

“(They’re) like my second family,” he said. “I was with him when (Dowling and his sister) were born.”

Riddick described Dowling’s upbringing as “wholesome.” His mother, a nurse, and father, who works in the music industry, have been married for many years.

“There was no issues or problems in the past,” Riddick said. “He was a good kid.”

Riddick never witnessed the teen exhibit unhinged behavior, he noted. The news of the slaying caught him off guard, making him think the killing was a “freak situation.”

“Something must’ve made him snap like that,” Riddick surmised. “That’s not his type of demeanor on a typical day. He was a cool, quiet kid. He’s not a kid to scream and yell.“

The friend has been unable to speak with Dowlings’ distraught father since the murder.

“I couldn’t even make out what he was saying,” he said of the elder Dowling. “I know he’s hurt. When I spoke to him on the phone, I could hear the pain in his voice and the tears. So I rushed over here.”

Riddick emphasized how close Dowling was with his family and didn’t believe the teen ever even acted out at home.

“He never told me that he had an altercation with his son,” Riddick said of Dowling’s father. “His father is the kinda guy to stay on top of things. If he needed to address something, he would’ve addressed it. He was on point with him, he kept track.

“Brian and his father had a good relationship,” he added. “With his mom, too. They are one unit.”

Riddick watched the gruesome surveillance footage that caught the moment Dowling lunged at and stabbed Carson to death.

“When the video came out and I saw that it was him, I was like, I can’t believe that’s Brian’s son,” the friend said. “You could see that something was bothering him to make him react that way. He was upset about something. And I know it wasn’t anything at home.”

Tears streamed down Dowling’s face as he was led from the neighborhood’s 81st Precinct stationhouse Wednesday afternoon.