villain of the piece, the

the villain of the piece

The person or thing most responsible or at fault for a bad situation or outcome. The company's safety supervisor cut corners on expensive safety equipment, but the real villains of the piece are the executives of the company who demanded that he keep costs down by any means necessary. Though they thought he'd left the gas oven on, it turns out that a faulty gas line was the villain of the piece.
See also: of, piece, villain
Farlex Dictionary of Idioms.

villain of the piece, the

The person to blame for what is bad or wrong, as in I'm afraid the caterer is the villain of the piece-the food wasn't ready for hours. The piece in this term alludes to a play in which the villain is the character whose evildoing is important to the plot. [Mid-1800s]
See also: of, villain
The American Heritage® Dictionary of Idioms by Christine Ammer.
See also:
  • the villain of the piece
  • villain
  • villain of the piece
  • There is safety in numbers
  • there's safety in numbers
  • check in on (someone or something)
  • slice through
  • slice through (something)
  • cover (one's) bases
  • (it) doesn't matter
References in periodicals archive
There's also his mother Franny, Uncle Gaston, Uncle Art, Grandpa Bud and the apparent villain of the piece, the Bowler Hat Guy and his hat, Doris.