Sanford Levinson, a visiting Harvard Law School professor who is of Jewish heritage, opened his mail Monday morning to find a postcard scrawled with hateful, anti-Semitic language.

In the anonymous, handwritten card, the author first addresses Levinson by his lifelong nickname, “Sandy.” The brief postcard, which includes threatening, explicit, and anti-Semitic attacks on Levinson, ends with: “We’re gonna drain the swamp at Harvard Law. Juden Raus!”

Based on its stamps, the postcard appears to have been mailed from England, Levinson said. Levinson, age 75, is a full-time professor at the University of Texas at Austin, where he teaches government and law. {shortcode-074d5b1bb1e585839bbab6318ce24b7aa4572218}

The sender’s call to “drain the swamp” at the Law School seems to be a reference to a slogan made popular by President-elect Donald Trump during the election. Over the course of his controversial campaign, Trump often said he would “drain the swamp” in Washington, promising to remove corporate lobbyists and Wall Street executives from positions of power.

“I have been writing a lot of stuff that’s very, very anti-Trump, and I have to assume that’s what triggered it,” Levinson said in an interview Wednesday. “I blog a lot and I’ve written op-eds and the like so I’ve certainly gotten angry responses before, but nothing like this.”

“This is just different, it was remarkably anti-Semitic,” said Levinson, who has taught at Harvard as a visiting professor for the past 12 years.

The postcard’s closing words, “Juden Raus!,” refer to a German board game from the 1930s in which players had to collect small tokens representing Jewish people and gather them at a “collection point,” according to the website for Public Radio International. “Juden Raus!” translates to “Out with the Jews!”

The postcard—and its contents—were reported by The Boston Globe on Tuesday.

Soon after reading the card, Levinson contacted Law School Dean Martha L. Minow and the Harvard University Police Department. Levinson said HUPD officers visited his office Monday to speak with him, but that he doubts there is much they can do.

HUPD spokesperson Steven G. Catalano said Wednesday that the department is conducting an “open and active investigation” into the postcard, but declined to comment further.

The hate mail arrived at a time when reports of racially charged incidents have spiked across the country—and on Harvard’s campus. Last week, a handful of University affiliates said they were harassed, both verbally and physically, by strangers on the basis of their ethnicity or disabilities.

Also last week, University President Drew G. Faust sent an email to students, faculty, and staff decrying the “escalating numbers of cruel and frightening incidents” that have taken place since the election. Citing Faust’s message, HUPD Chief Francis D. Riley on Monday sent an email encouraging Harvard affiliates to report bias-related incidents and hate crimes to campus police.

Levinson said he sees a “connection” between the presidential election and the recent uptick in hateful language and action. In particular, he said he believes people feel “freer” after the election to make “racist, anti-Semitic, or anti-female” comments.

“I do think that the campaign and Trump scrutiny has liberated a certain kind of dialogue,” Levinson said. “I think there is just this sense, at least for awhile and maybe it will be for the next few years, that certain sorts of restraints are now loosened.”

Since The Globe reported the story, Levinson said he has received “very gratifying” messages of support from both friends and strangers. But ultimately, Levinson said he wants to move on from the postcard.

“I think the best response is to say, ‘It’s really terrible that there are people like this in the world,’ but then to go on with your life,” he said.

After opening the postcard Monday, Levinson, a constitutional law scholar, said he sat down and got back to work.

—Staff writer Hannah Natanson can be reached at hannah.natanson@thecrimson.com. Follow her on Twitter @hannah_natanson.