The presidential campaign of Democratic primary candidate Sen. Bernie Sanders (D-Vt.) has suspended an activist recently hired as the campaign’s Jewish outreach coordinator after she was found to have posted profanity-laced social media messages about Israeli Prime Minister Benjamin Netanyahu.

Simone Zimmerman is active in the self-described “pro-Israel, pro-peace” lobby J Street and the “Open Hillel” movement—both of which have been criticized in the Jewish community for ignoring Israeli grievances in the Israeli-Palestinian conflict and whitewashing Palestinian terrorism. Open Hillel rejects the Hillel campus umbrella organization’s guidelines on shunning partnerships with anti-Israel groups, while J Street has also been scrutinized for co-sponsoring events with anti-Israel organizations. Zimmerman has also been involved with IfNotNow, a new movement of young American Jews who oppose Israeli control in the disputed territories.

In a February op-ed for Haaretz, Zimmerman outlined her views on Israel, including her perceptions on what she called “grave injustices committed by the Jewish state” and the “disastrous reality of holding millions of Palestinians under military occupation.”

“Tell the UC Regents: anti-Zionism is not racism, it’s a political belief,” Zimmerman retweeted from the Twitter account of the anti-Israel group Jewish Voice for Peace in March, reacting to the University of California Board of Regents’ adoption of a report that condemned both anti-Semitism and forms of anti-Zionism that are anti-Semitic.

The initial decision to hire Zimmerman came after Sanders recently inflated the number of Palestinian civilian deaths in the 2014 Israel-Hamas war at least sevenfold—to 10,000—in an interview with the New York Daily News.

In the wake of Zimmerman’s hiring, her past Facebook posts came to light, including one in which she wrote, “Bibi Netanyahu is an arrogant, deceptive, cynical, manipulative asshole,” and “F**k you, Bibi, for daring to insist that you legitimately represent every fraction of the Jewish world.” She later edited those posts to remove the profanity.

The former head of the Anti-Defamation League, Abraham Foxman, wrote in an email to Jewish Insider that Sanders “needs to fire Simone Zimmerman” because “no amount of word changes can cure her ugly characterization of the prime minister of Israel and the Israeli army and people defending themselves.”

Sanders’s spokesperson, Michael Briggs, told the New York Times that Zimmerman has “been suspended while we investigate the matter.”