A NYPD officer fatally shot a knife-wielding man who slashed him in the neck, authorities say.

Police Commissioner Bill Bratton said that 24-year-old Fillippo Gugliara was stabbed with an 11-inch hunting knife while trying to apprehend a man who had just assaulted a 78-year-old woman in Coney Island.

The suspect slashed the officer in the collarbone, then fled, prompting Gugliara to fire two rounds at the suspect.

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The officer’s bulletproof vest is credited with saving his life.

Newsday reported:

Bratton, with Mayor Bill de Blasio at a hospital news conference, said that Gugliara followed his training. "[He] did the right thing, went toward the danger," de Blasio said. "Was so good to see him, thank God, in great shape."

Gugliara was on patrol as part of a police "Safe Passage" program to help children get to and from school, said transit police chief Joseph Fox."All accounts are, our initial review, is that the officer performed admirably," Bratton said. "Quite clearly he faced a life-threatening situation with this individual."

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