By Daniella Silva

The so-called caravan headed towards the southern border has not just united migrants and refugees from Central America, experts who research extremism say it has also brought together a spectrum of conspiracy theorists and the far-right.

The possible prime example of that at the moment is Robert Bowers, the man accused of killing 11 people Saturday at a Pittsburgh synagogue. He had posted on the social network Gab prolific anti-Semitic threats as well as conspiracy theories surrounding the caravan of migrants traveling north from Honduras towards the U.S. border.

Experts on extremism said myriad elements of the right has seized on imagery from the caravan to provoke a variety of fears.

"The migrant caravan works for the far-right on multiple levels," J.M. Berger, a research fellow at VOX-Pol, a violent online extremist research group, wrote to NBC News in an email. "Fear and hatred of immigrants is a theme that can cross ideological boundaries for a lot of different far-right movements — for instance, it can be a vehicle for anti-Muslim views or for white supremacist views, and it can be couched as anti-immigration, when in fact, it's targeting the immigrants themselves."

Peter Montgomery, a senior fellow at Right Wing Watch, which tracks far-right media, said the caravan was being used by some on the right to "inflame fears" from different angles, which can target those who believe in strict immigration policies, people with national security concerns, white nationalists, among others.

Those narratives were not just being circulated on sites like Gab and 4chan, but being touted by Fox News and other conservative media and figures, including President Donald Trump, he said.

"This group of people seeking refuse and asylum have been turned into an invading army by Trump and by his ring-wing supporters who are using the language of invasion," he said.

Trump has repeatedly called for stopping the caravan and has claimed without providing evidence that Middle Easterners and criminals are among the migrants.

"Many Gang Members and some very bad people are mixed into the Caravan heading to our Southern Border," Trump tweeted Monday. "Please go back, you will not be admitted into the United States unless you go through the legal process. This is an invasion of our Country and our Military is waiting for you!"

On Monday, the Pentagon announced that the U.S. would send thousands of troops to the border as a response to the caravan.

Montgomery pointed to several instances of conservative figures fanning some of the conspiracy theories about the migrant march. Florida Rep. Matt Gaetz questioned without providing any evidence whether Soros had organized and was funding the caravan in mid-October.

One conspiracy theory surrounding the caravan is that Jewish organizations or individuals such as George Soros, a Hungarian American Holocaust survivor, are allegedly funding the caravan.

Last week, Matt Schlapp, the chairman of the American Conservative Union, repeatedly questioned who was "paying for the caravan" on CNN. And Televangelist Pat Robertson urged Trump to launch an investigation into allegations that Soros was funding the caravan.

On Monday afternoon, Fox News guest David Ward, a former agent with Immigration and Customs Enforcement, said without providing evidence some migrants may have diseases such as "small pox and leprosy" that could "infect our people in the United States."

Meanwhile, Fox News anchor Shep Smith warned viewers against fear-mongering reports about the caravan. "There is no invasion. No one is coming to get you. There is nothing at all to worry about,” he said.

Bowers’ posts are tied to a viral image that appeared to show migrants hopping onto a truck with a Star of David on the side. That image was circulated widely on far-right forums. He posted a screenshot of video of the caravan that aired on Fox News as well as other networks, that does not mention the symbol.

And hours before the attack, Bowers posted alleging that the Hebrew Immigrant Aid Society, or HIAS, a humanitarian nonprofit group that assists refugees, was bringing in “hostile invaders” to the U.S. who commit violence against “our people.”

"A common white supremacist conspiracy theory is that Jews are behind efforts to impose mass immigration in the U.S. with the goal of destroying the white race," said Oren Segal, the director of the center on extremism at the Anti-Defamation League.

Soros has been frequently targeted by conspiracy theorists. The liberal philanthropist who also was targeted in a series of package bomb mailings last week and there were several posts on the Facebook pages of suspect Cesar Sayoc's was the only Facebook follower of two pages called "Killgeorge Soros" and "Killall Socialist."

"White supremacists view immigration, diversity, multiculturalism as the hallmark of their upcoming destruction and, because of their anti-Semitism, they view the Jews as controlling or being responsible for those issues," he said.

Berger said he believed the main reason why this issue was "rising to the top now is that President Trump has elevated it.”

"With his statements, policies and tweets, he has pushed this issue into the mainstream media and framed it in a way that is very friendly to extremist fears," he said.