The victim, identified as Rhonda Scott, 38, suffered several stab wounds and was severely burned, according to police.
Two manhole covers were blown off in Manhattan Saturday, shattering glass at a nearby furniture store, according to fire department officials.
The covers were blown off at around 2:30 p.m. Saturday at 200 Madison Avenue, near 35th Street.
The FDNY said there were no injuries, but the building at 200 Madison Avenue was evacuated briefly due to high levels of carbon monoxide.
The residents were back in the building at 4 p.m.
The cause of the explosion is still under investigation.