Killer set off explosion after stabbing man to death in NYC apartment

A man was fatally stabbed inside his Queens penthouse Tuesday — and his killer then set off a massive explosion that blew the roof off the apartment building to try to cover up the murder, police sources say.

The blast tore apart the top-floor apartment and parts of the floor below inside the seven-story building on 41st Avenue near 73rd Street just before 10:30 a.m., fire officials said. Fire responders found the 26-year-old man as they battled the four-alarm blaze in Jackson Heights. He was pronounced dead shortly after by EMS.