The victims are all members of the same family and are identified as two parents and two of their three children.
The fire broke out at the private home on South Bond Street, off Mount Vernon Avenue, around 3:30 a.m.
The victims lived in a basement apartment in the multi-family home, and their main path in and out of the house was blocked by a car parked near the door that was also engulfed in flames. Investigators believe the fire started inside that car and then spread to the home. It is not considered suspicious.
Investigators believe it may have been sparked by a short circuit in the car's stereo equipment.
Killed were dad 60-year old Alcedo Urera, his wife 39-year old Nancy, 21-year-old son Jesus and 17-year-old daughter Mariselis. Their 19-year-old son, Reymundo, survived and is in the hospital with second degree burns to the face and body.
The family is from the Dominican Republic and has lived in the house for the past two years.
"We just got a call saying the house was on fire, and we got here, we were just hoping that they were all alive," the victims' grandson Richard Fernandez said. "When we got here, they said everybody was dead."
All three children initially made it out, but went back in to try and save their parents. Nancy and Mariselis Urera were found huddled together.
It is a devastating loss in the community where many extended family members of the victims live.
"They were like the family in this neighborhood that everyone would go visit and go in the house or the backyard," nephew Jose Brito said. "They'd make coffee about 20 times a day for everybody."
Firefighters were faced with heavy smoke and flames when they arrived on the scene, and frantic attempts to rescue the victims failed.
When the firefighters rushed down the stairwell to the basement, they were initially blocked by a bolted door.
Three firefighters were also injured.
Investigators are looking into whether or not the house was illegally subdivided into apartments.
They also believe that Reymundo inadvertently made the fire worse by leaving the door open, then kicking in an air conditioner on the other side of the house trying to get in, creating a blowtorch effect.