Officer Dennis Guerra, 38, succumbed to his injuries at 6:50 a.m., according to the New York Police Department spokesman, Sgt. Lee Jones. The husband and father had more than seven years on the job.
Guerra and his partner, Rosa Rodriguez, were overcome by carbon monoxide and smoke as they responded to the suspicious fire Sunday on the 13th floor of the Coney Island apartment building. Rodriguez remains hospitalized in critical condition.
Mayor Bill de Blasio led a moment of silence for the fallen officer at an unrelated event Wednesday.
"We've lost a good man this morning," de Blasio said. "We had a very brave police officer Dennis Guerra who did something that most of us wouldn't understand how to do.
"He went towards those in danger no matter the risk to him. It's something that our police officers do every day, it's something our first responders do every day, it's something we need to appreciate every day."
Police allege a 16-year-old boy set fire to the mattress out of boredom. He was arraigned Monday on charges of assault, arson and reckless endangerment and held without bail.
"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," Police Commissioner William Bratton said at a news conference Tuesday before the officer's death. "How can any of us make any sense out of that? And particularly with the tragic consequences that ensued."
"We pray that every young person who hears of the tragic passing of hero police officer Dennis Guerra and of the suffering of officer Rosa Rodriguez and their families learns that there deadly consequences that result from foolish actions," said Patrick J. Lynch, president of the Patrolmen's Benevolent Association. "We must learn from this tragedy so that their sacrifices will not have been made in vain."