Authorities are investigating a grisly discovery at an under-construction public school in Queens.
A body was found in a chimney at P/S./ I.S. 113 Anthony J. Pranzo in Glendale after a janitor smelled something pungent coming from there and called an exterminator, according to a law enforcement source.
The exterminator opened the ash dump and found a shoe, the source says. Then, he felt a foot…