A 22-year-old man is accused of killing his father and 12-year-old sister at home with his younger brother, 9, witnessing it.

Michael J. Andreev Jr. has been arrested and charged with two counts of murder and a weapons charge in Sunday's killings, the Syracuse Post-Standard reported.

Trooper Jack Keller, a spokesperson for the state police, said Andreev Jr.'s young brother witnessed the stabbing attack but did not say if the boy was harmed.

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Responders pronounced Michael J. Andreev Sr., 67, and Sofia Trusova, 12, dead upon their arrival to the home in Jordanville, a hamlet of Warren, which is about 20 miles southeast of Utica, New York.

Police say Andreev Jr. was found injured outside the home and was taken to a hospital for treatment. He was arrested upon his release from the hospital and is being held without bail.

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An email was sent to the Herkimer County district attorney's office seeking attorney information for Andreev Jr.