Robert Rivera was charged with second-degree murder, Suffolk County police...

Robert Rivera was charged with second-degree murder, Suffolk County police said. At right, the scene in Baywood on Friday night. Credit: SCPD; Joseph Cassano

A Baywood man walked behind his teenage brother as he was playing video games and fatally stabbed him in the neck Friday night, prosecutors said.

Robert Rivera, 19, was charged with second-degree murder in the killing of his brother Brian Castillo, 17, at their North Thompson Drive home, prosecutors and Suffolk County police said.

Rivera appeared in a Central Islip courtroom Saturday morning wearing an open white jumpsuit and asked whether his parents were in the courtroom. His attorney denied the charge on behalf of his client, who was ordered held without bond.

Rivera walked into the bedroom where his brother was playing video games and stabbed him at least once in the neck with a knife, Assistant District Attorney Lawrence Opisso said.

Castillo went to the front yard where he saw his father and “made a dying declaration, ‘look what Robert did to me,’ ” Opisso said.

His father attempted to take him to the hospital, but Castillo collapsed and died on the front lawn, Opisso said. Police were called to North Thompson Drive in Baywood, near North Bay Shore, just after 7:20 p.m., police said, and Castillo was pronounced dead at the scene.

Prosecutors said Rivera ran away and was arrested 20 minutes later, found walking near the Sagtikos State Parkway.

During questioning by police, Rivera gave a full videotaped confession, Opisso said.

A court-appointed attorney for Rivera, Steve Fondulis, said Rivera had a history of mental illness and needed psychiatric medication. He said he requested a psychiatric exam to ensure he was treated in custody and a jail suicide watch.

“There seems to be a psychiatric background,” Fondulis said. “I know nothing about what happened in that house.”

Family members and the mother of both teens wiped away tears after the arraignment but declined to speak with reporters.

Rivera is set to return to court Aug. 30.

"We're speaking with his family about his background and what his possible motive might've been," Suffolk County police Homicide Det. Lt. Kevin Beyrer said at the scene on Friday night.

Earlier in the evening, at one end of the cordoned-off street, a woman who said she was the mother of the victim pleaded in Spanish with police to let her cross the police line and walk past the crime scene to the other end of the street, where her husband was. She was directed to drive up a parallel street, and walking with a friend to a car, the woman started crying and declined to comment.

As investigators collected information at the scene, about 10 people from the victim's church gathered at the corner of North Thompson Drive and Pine Aire Drive.

Dalila Martinez, secretary for the Seventh-day Adventist Church in North Bay Shore, said the victim's mother had called church members.

"We're like a family and we want to be with her," Martinez said. "If something happens to one of us, it happens to everybody."

CORRECTION: North Thompson Drive is in Baywood. An earlier version of this story included an incorrect community.

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