NEW YORK (AP) – A school bus driver and his nephew died as a fire ravaged their apartment Sunday, a day after the city’s deadliest blaze in nearly two years killed a couple and three children, authorities said.

The latest fatal fire came as the lone survivor of Saturday’s fire, a 10-year-old boy, remained hospitalized with critical injuries.

His family’s apartment became a deathtrap in just minutes, firefighters said.

Authorities were investigating the causes of both fires, which erupted on a warm autumn weekend.

All seven victims died of smoke inhalation, said Ellen Borakove, a spokeswoman for the city medical examiner’s office.

Sunday’s blaze was reported shortly after midnight in Brooklyn’s Bushwick neighborhood.

The fire killed Shawn Monderson, 33, and Cemioni Fraser, 12, the medical examiner’s office said. Relatives said the two moved into the row-house apartment just last week.

Cemioni, Monderson’s nephew, was living with his uncle because his mother had returned to Guyana, the family said.

“It’s a family tradition that we look out for each other,” Frederick Monderson, the bus driver’s uncle, told the Daily News. Shawn Monderson had recently become a U.S. citizen, his uncle said.

In Saturday’s fire, six members of one family were found unconscious, huddled in the bathroom and bedroom of their apartment in Manhattan’s Chelsea neighborhood. Only the boy survived.

Jacobi Medical Center declined to provide an update on his condition Sunday evening, citing privacy laws. Fire officials said earlier that the boy was in critical condition, placed in a hyperbaric chamber that supplies emergency oxygen to burn victims.

The fire was the city’s deadliest since a March 2007 blaze in the Bronx killed 10 people, including nine children, officials said.

Saturday’s fire started at about 6:30 a.m. in the kitchen of the family’s home in the Robert Fulton public housing complex.

Thick, black smoke quickly filled the apartment and kept the six from escaping through the front door, fire officials said. There was no fire escape.

The Fire Department said the apartment’s smoke detector had been unplugged and its battery removed.

The smoke detector was inspected six months ago and was working, according to New York City Housing Authority officials.

A working alarm might have alerted the victims in time in time for them to flee, deputy fire chief James Daly said.

Saturday’s victims were identified as the 40-year-old father, Maschay Joa Valdez, the 34-year-old mother, Delkis Balbuena; and three girls, 8-year-old Nancy Joa Balbuena; 2-year-old Bet-el Joa Balbuena, and Ruth Joa Balbuena, 15 months.

Police did not release the name of the 10-year-old boy. Neighbors identified him as Jonzan Joa Balbuena and said he and his family were immigrants from the Dominican Republic.

Firefighters worked quickly, shattering windows and extinguishing flames about 45 minutes after the blaze began. Some wept as they carried out the lifeless bodies.