This week, George Mason University is hosting a conference promoting the Boycott, Divestment and Sanctions (BDS) movement, an anti-Israel campaign that has recently swelled its ranks by participating in "solidarity work" with sympathetic organizations. But as the BDS campaign has grown, its "big tent" philosophy may have attracted organizations with ties to terrorism.

In May 2016, for example, the Miami-based organization Dream Defenders flew a group of activists that included a Florida lawmaker to Israel and the Palestinian territories. While in the West Bank, participants were led by a tour guide identified with the terrorist group Popular Front for the Liberation of Palestine (PFLP).

This connection with the PFLP is not new for Dream Defenders. They have expressed support for the PFLP on Facebook, Twitter, and Instagram. The group's executive director is Ahmad Abuznaid, the son of the PLO's ambassador to the Netherlands. He has posted pictures of himself embracing Rasmea Odeh, a now infamous PFLP terrorist who was involved in the bombing of an Israeli Supermarket in 1969. Abuznaid also spoke at a fundraiser on Odeh's behalf.

Odeh is now a cause célèbre for BDS activists in the United States. Boycott advocates have rallied to her defense, raising funds for her while she faces prosecution in the United States for immigration fraud (for lying about her time in prison). Odeh's boosters include BDS-supporting groups like Palestine Legal, Jewish Voice for Peace, and American Muslims for Palestine. Her defenders contend she was wrongfully convicted by Israel in the 1969 bombing (Odeh herself appears in a 2004 documentary discussing her involvement).

Another BDS group in America with connections to the PFLP is "The US Coalition to Boycott Israel," or the "Coalition for Justice in Palestine." While apparently not officially registered as a business or as a nonprofit, this organization claims to work with several groups in the BDS space. The Coalition is, according to available information, coordinated by Senan Shaqdeh, a figure described on the PLO's website as a former PFLP "mountain fighter" in Lebanon.

It is unclear whether Shaqdeh is still active with the PFLP. But he has helped to coordinate a number of BDS and anti-Israel protests in Chicago and across the country. Curiously, in 2014, he travelled to Ramallah, where he met with Palestinian President Mahmoud Abbas and Prime Minister Rami Hamdallah.

The BDS campaign in the United States broadly identifies as a nonviolent social justice movement. But, its connections to the PFLP, a decidedly violent group, are troubling.

Founded in 1967 as a Marxist-Leninist revolutionary organization by George Habash, the PFLP was known for a series of plane hijackings in the late sixties and seventies. They placed bombs in supermarkets, gunned down civilians, and hired assassins to massacre passengers at Israel's Lod Airport in 1970. The group was designated in 1997 as a Foreign Terrorist Organization by the State Department, and it remains on the list to this day.

While it is still believed to be the second largest faction within the Palestine Liberation Organization (PLO), the PFLP is no longer as influential as it once was. But the PFLP remains active in the West Bank and the Gaza Strip, not to mention Palestinian refugee camps around the Middle East. And its commitment to violence has not changed.

In 2011, two PFLP members carried out the murder of a family in the West Bank settlement of Itamar (including a 3-month-old infant). They were responsible for a 2014 shooting in West Jerusalem that killed five and wounded eight. Open-source reports indicate that the group has recently seen an uptick in funding from Iran.

The PFLP and BDS nexus is not limited to the United States. The group is increasingly active among BDS groups in Europe.

In 2013, Shawn Jabarin, the director of the Palestinian NGO Al-Haq, visited France, where he lectured for several organizations and granted interviews about boycotting Israeli goods. Jabarin was denied travel visas by Israel, and was flagged by Israel as being a PFLP activist in the 1980s and 1990s.

Recently, the PFLP sent its most famous member, the first woman hijacker in history, Leila Khaled, on speaking tours worldwide. In April 2016, she visited the German organization Falestin Beytona, the Offices of the Communist Party of Sweden in Gothenburg, and the Austrian-Arab Cultural Center (OKAZ) in Vienna – all organizations that support BDS. Khaled was also the guest of the BDS movement of South Africa in 2015.

Khaled position on violence has not changed. She sees BDS as a means to an ends. In a 2015 op-ed, she notes that BDS "sustains our resistance and our revolution," But she also notes that, "refusing to buy products in a store or cancelling a corporate contract will not liberate Palestine. Nothing but the Palestinian struggle and resistance in all of its forms, from refusing the orders of an occupation soldier to marching in protests to armed struggle, will liberate Palestine."

The BDS campaign has always been controversial. It is, in essence, an effort to wage economic warfare against Israel. Whatever legitimacy it has garnered comes largely from claims that it eschews violence. But the campaign's growing ties to the PFLP tell another story, seemingly validating the harshest accusations leveled against it.

Jonathan Schanzer is vice president for research at Foundation for Defense of Democracies, where Kate Havard is a research analyst.