NEW YORK (CBSNewYork) – A John Jay College economics instructor has been placed on administrative leave over a tweet about “dead cops,” the school says.

The college is a criminal justice school.

“It’s a privilege to teach future dead cops,” Michael Isaacson posted.

He is a vocal anti-fascist who has blasted police in the past, WCBS 880’s Peter Haskell reported.

College President Karol Mason called the comments “abhorrent.”

“This adjunct expressed personal views that are not consistent with our college’s well known and firm values and principles and my own personal standards and principles,” she said in a statement. “I am appalled that anyone associated with John Jay, with our proud history of supporting law enforcement authorities, would suggest that violence against police is ever acceptable.”

Mason said Isaacson was immediately placed on administrative leave as the school reviews the matter.

But leaders of local police unions want him fired, Haskell reported.

Mayor Bill de Blasio said New York City will not stand for the anti-police rhetoric and neither should the college.