Suffolk County, NY – A 19 year old murdered his little brother last Friday night as the 17-year-old played a video game.

Newsday reported that Robert Rivera had walked into the bedroom where Brian Castillo was playing video games at about 7:20 p.m. on Aug. 24 and stabbed him in the neck from behind with a knife at least once.

After he was stabbed, Castillo went into the front yard of their home on North Thompson Drive and told his father “look what Robert did to me” before he collapsed, according to Assistant Suffolk County District Attorney Lawrence Opisso.

The district attorney said that he considered that the victim's "dying declaration."

The boy’s father called 911 and when police responded to the home, they found Castillo with a stab wound to the neck. He was pronounced dead at the scene, according to WNYW-TV.

Rivera fled the home before police arrived, but officers found him 20 minutes later as he was walking along a highway.

The older brother gave a taped confession to his little brother’s murder, the district attorney said.

“We're speaking with his family about his background and what his possible motive might've been," Suffolk County Police Lieutenant Kevin Beyrer, a homicide detective, told Newsday.

Rivera was arrested and charged with second-degree murder, according to WNYW.

Steve Fondulis, Rivera’s court-appointed attorney, said his client had a history of mental illness and needed psychiatric medication.

Fondulis said he has requested a psychiatric evaluation of his client to make sure Rivera was treated while in custody. He also requested a suicide watch on his client in the jail.

Rivera appeared in court last Saturday, and the judge ordered him held without bond.

Family members and the brothers’ mother were in court in tears, but they refused to speak with reporters.