His father is dead. His mom is in jail charged with murdering his dad. The outburst of violence thrust the eldest son of Kathleen and Ralph Prisco into the role of caretaker for his two siblings.

Just a few months ago, Matthew Prisco, 22, a recent Princeton University graduate, was worrying about finals. Now, he must watch over his sister, Melissa, 19, and brother, Christopher, 16.

"Melissa may well be the strongest of all of us. She's been there for me when I had my moments," Matthew Prisco said in an interview Thursday, referring to stretches of time during the past week when he felt overwhelmed. "I can't speak enough how important family is in all of this."

During the hourlong conversation, Prisco was adamant about not discussing the horrific scene that played out inside the family's sprawling home on Bob O Link Lane in Fort Salonga on the morning of Oct. 30.

According to Suffolk police, he heard a struggle in his parents' master bedroom on the second floor and his father screaming for help. The son's frantic 911 call brought police to the home, where officers found Ralph Prisco, 54, bleeding in the foyer. A kitchen knife, which police believe was used to stab him more than a dozen times, was found near his body.

Matthew Prisco was the only person in the house with his parents at that time, police said.