Dennis Guerra, one of the police officers who were rescued from Sunday's fire in a Coney Island high-rise apartment, passed away on Wednesday morning.
Police said Guerra, 38, passed away at around 6:50 a.m. at the Montefiore Medical Center in the Bronx.
A father of four with eight years in the force, Guerra and fellow officer Rosa Rodriguez, 36, took an elevator up to the blaze at 2007 Surf Ave. but were overcome with smoke as soon as they entered the hallway.
Firefighters rescued both after finding them in the hallway, unconscious and unresponsive on the floor.
EMT workers resuscitated Guerra outside the burning building before he was taken to the hospital to be treated for carbon monoxide poisoning and smoke inhalation.
Rodriguez remains in critical condition at the NewYork-Presbyterian/Weill Cornell Medical Center, officials said.
Marcell Dockery, 16, was arrested on Monday in connection to the fire, reportedly confessing to investigators that he lit a discarded mattress because he was "bored."
The teen, who lives in the Coney Island apartment building, was charged with arson, assault and reckless endangerment, but might face more severe charges with Guerra's passing.
Mayor Bill de Blasio and Police Commissioner Bill Bratton visited the officers' bedsides on Tuesday. At an unrelated press event that same day, Bratton discussed Dockery's alleged actions.
"The tragedy here is that a 16-year-old young man would not have common sense enough to understand the potential implication of lighting a mattress, as has been alleged, on fire in his own building," Bratton said. "How can any of us make any sense out of that?"