NEW YORK, NY October 12, 2008 —A 10-year-old boy is fighting for his life, after a Manhattan fire killed his parents and three young siblings in just minutes.

REPORTER: The boy is in critical condition at Jacobi Hospital in the Bronx. Autopsies are to be performed today on those killed when fire swept through their seventh-floor apartment at the Robert Fulton public housing complex in Chelsea. Deputy Fire Chief James Daly says the smoke detector did not appear to working.

DALY: The smoke alarm appears to be hard-wired with a battery backup. I can tell you there's no backup battery in there. So right now, the marshall's going to investigate.

REPORTER: The city's Housing Authority says the smoke detector was inspected six months ago and was working. Officials say it's the deadliest New York fire since 10 people, including nine children, died when their Bronx home caught on fire in March 2007.