The shooting happened on Saturday afternoon in the Village of Warwick.
Officers were called to a home over a domestic dispute. Police say a man in his thirties was told by an officer to put the knife down.
When he refused to comply, he was shot and pronounced dead at a nearby hospital.
The Warwick Police Officer who opened fire has been placed on administrative leave. He has not been identified.
There were no other injuries.
The case will go to a grand jury to determine if the shooting was justified.
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Orange County D.A. David Hoovler and Warwick Police Lt. Thomas Maslanka gave me an on camera presser at the scene.