A New York professor drew ire from City University administrators and law enforcement officials because of a tweet in which he said teaching “future dead cops” is “a privilege.”

Michael Isaacson, an adjunct professor at CUNY’s John Jay College of Criminal Justice, was placed on administrative leave because of the three-week-old tweet, which appears to have recently caught the attention of the college’s president and New York City’s largest police union.

In a tweet on Aug. 23, Isaacson, who teaches economics, said: “Some of ya’ll might think it sucks being an anti-fascist teaching at John Jay College but I think it’s a privilege to teach future dead cops.”

In a statement Friday, John Jay College President Karol V. Mason called Isaacson’s comments “abhorrent” and the “antithesis” of an academic institution that trains future law enforcement. While she said that professors have a right to free speech and academic freedom, “expressions of hate or intimidation are not welcome in that civil discourse.”

“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. 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.

Mason added that faculty members and students have been threatened as a result of the tweet, and Isaacson was placed on administrative leave for safety reasons.

In an email to The Washington Post, Isaacson, an anti-fascist activist, said he “unequivocally” supports the college’s decision “in the interest of public safety,” and he apologizes to faculty members and his students for placing them at risk.

“I am saddened that I cannot continue to teach my students, but I value their safety and the safety of the John Jay community above all else,” he said, adding later: “My [principal] regret is that I put people at risk who did not assume that risk voluntarily.”

The decision to place Isaacson on administrative leave was announced on the same day that the Patrolmen’s Benevolent Association of the City of New York, a union that represents 50,000 active and retired police officers, called for Isaacson’s firing.

Patrick J. Lynch, the union’s president, railed against what he described as “disgusting anti-police attitudes” and “gleeful embrace of political violence.”

“It is absolutely outrageous that an individual who holds and expresses these views could be employed by any academic institution, much less one that counts an overwhelming number of New York City police officers as among its students, alumni and faculty members,” Lynch said in a statement.

Isaacson will remain on administrative leave while university officials review the matter, Mason said.

New York Police Commissioner James O’Neill and New York Mayor Bill de Blasio (D) also have weighed in:

Isaacson shot back at de Blasio in a series of tweets Saturday. He said the mayor, whose rift with the city’s police force is well documented, attacked free speech, academic freedom and John Jay College’s administrative autonomy.

According to Isaacson’s résumé, he began teaching economics at John Jay last year. Before that, he was a lecturer at Long Island University, New York University and Howard University.

Though many of his students intend to go into law enforcement, he said he teaches them the “economic reality” of that career choice. He said he hopes to encourage his students “to think critically about what they hope to offer their communities and whether law enforcement is the best avenue to achieve that.”

He said that law enforcement as an institution operates in the interest of the weapons and prison industries, and not the communities it’s sworn to serve.

“Every bullet fired is revenue for the weapons industry. Every prisoner is revenue for the prison industry,” he said, adding that policing as an institution has disproportionately placed a burden on low-income people and communities of color.

In a statement posted Friday on Twitter, he said he hopes his students can find a career path “that does not put them in the position of having to act as an agent of that institution.”

Isaacson describes himself as an anti-fascist and anarchist and has said that he believes President Trump is a fascist.

He said the media has misrepresented anti-fascist activists, or antifa, as members of a violent group and ignored “the vast majority” of advocacy work that does not involve violence and tries to avoid physical conflict. Anti-fascism, he said, is about “engaging and serving communities” against the threat from white supremacists, Nazis and the Ku Klux Klan.

But as a result of violence hyped in the media, many have joined the antifa ranks “purely on the basis of thrill-seeking rather than community support,” he said.

Last month, however, images broadcast across the country showed dozens of anarchists and antifa members, their faces hidden behind black bandannas and hoodies, jumping over barricades at the Martin Luther King Jr. Civic Center Park in Berkeley, Calif., and attacking a handful of Trump supporters and right-wing activists. In another controversial protest, dozens of antifa activists smashed windows and lit fires on the University of California campus in Berkeley in February, leading the university to cancel a speech by right-wing blogger Milo Yiannopoulos.

Isaacson defended his view in a combative Fox News interview Thursday with Tucker Carlson, who has described antifa as a “political militia that is doing the bidding” of Democratic politicians like House Minority Leader Nancy Pelosi (Calif.) and California Gov. Jerry Brown. Here’s part of the exchange:

Isaacson: I believe that communities have the right to defend themselves against threats against to themselves, to the community.
Carlson: Against ideas you don’t like?
Isaacson: No, against people who have explicitly said that they want to eliminate those people from our society.
Carlson: But you’re conflating violence with ideas.
Isaacson: No, I’m not.
Carlson: If I have not raised my hand to strike you, you have no right to strike me.

Isaacson is not the only professor to get in trouble with the universities they work for over a controversial statement.

In June, Lisa Durden was fired from Essex County College in Newark after she gave a confrontational Fox News interview, which was also with Carlson.

“Boo hoo hoo, you white people are angry because you couldn’t use your white privilege card to get invited to the Black Lives Matter’s all-black Memorial Day Celebration,” Durden said.

Another professor, Kathy Dettwyler, was fired the same month after she wrote on Facebook that Otto Warmbier, who was taken into custody in North Korea, then fell into a coma and died, was a “clueless white male” who “got exactly what he deserved.”

More recently, last month, Kenneth Storey was fired from the University of Tampa after he appeared to suggest in a series of tweets that Hurricane Harvey is karma for Texas for voting Republican.

The series of firings have drawn criticisms from the Foundation of Individual Rights in Education, which advocates for free-speech rights at American colleges and universities.

Ari Cohn, an attorney for the organization, said professors should be able to express diverse views and ideas in a public forum, as long as they’re not speaking on behalf of the academic institutions they work for. The firings, he said, could force faculty members to be silent for fear of offending people online and getting fired.

“Administrators, especially in recent months, have been capitulating to outrage mobs and firing professors left and right because they offended someone,” he said.

Michael E. Miller and Kyle Swenson contributed to this story.