A 17-year-old boy is dead after his 19-year-old brother fatally stabbed him while the younger brother was playing video games.

The New York Post reports that 17-year-Brian Castillo died after his brother Robert Castillo came up behind him and stabbed him in the neck as he was playing games at his Long Island home.

According to a Newsday report, Suffolk County Assistant District Attorney Lawrence Opisso said at Robert’s arraignment on Saturday morning the Brian stumbled into his front lawn, mortally wounded, and spoke to his father: “Look what Robert did to me,” the boy reportedly said.

Before his father was able to get him to a hospital, the 17-year-old collapsed and died. Emergency responders reportedly pronounced him dead at the scene.

Police apprehended Robert Castillo shortly after, though he had fled the scene on foot. They reportedly found him walking on Sagtikos State Parkway.

After his arrest, according to the Newsday report, Robert Castillo reportedly gave a video confession. The details of that confession are not known at this time.

The suspect’s attorney, Steve Fondulis, reportedly said that his client has a history of mental illness, and has requested a suicide watch as well as a psychiatric exam.

The motive for the apparent homicide is not known at this time.