The fire broke out inside a residence on Udall Road at around 5:53 a.m.
Third Precinct police officers responded to the fire and found two people deceased inside the home.
The deceased victims have since been identified as Matthew Kreamer, 24, and Kyle Dilegame, 16, who were brothers.
Joseph Dilegame, 54, and Toni Kreamer, 53, who also lived at the residence, were transported to Good Samaritan University Hospital in West Islip.
One of the two, Dilegame, was transported to Stony Brook University Medical Center for treatment of serious injuries.
Kreamer sustained non-life-threatening injuries.
Suffolk County Police Homicide and Arson Section Detectives are investigating the fire.
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