Eric Gaulin, 25, pleaded not guilty to the charges on Tuesday, April 15.
Gaulin and Bookstaver reportedly were gun enthusiasts and had been dating for four years at the time of the incident.
Gaulin and Bookstaver had just returned from the Palisades mall where they had purchased a new rifle. Gaulin was showing Bookstaver one of several rifles he owned at the time of the incident, according to the release.
Bookstaver's father said at the time of the incident it was a "horrible accident" but would not comment after the hearing in state Supreme Court in White Plains, according to LoHud.com.
Gaulin is reportedly the son of prominent entertainment lawyer Robert Gaulin.
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