Police in the city of North Tonawanda tell local media outlets that a police officer responding to a report of a domestic disturbance Wednesday night found 24-year-old Ralph Stone suffering from a stab wound to the chest.
The officer aided Stone at the scene, but he died before he could be taken to a hospital.
Officials say Stone's girlfriend, Jennifer Marchant, stabbed him with a kitchen knife. She was charged with second-degree murder and is being held in the Niagara County Jail without bail after pleading not guilty.
Police aren't commenting on what led to the stabbing.
Authorities say Marchant had acted in adult movies and worked as a collector for a suburban Buffalo bill collection agency.