On March 24, a shadowy group that calls itself Canary Mission posted a new feature on its website, “Uncovering Foreign Nationals,” in response to President Trump’s recent executive order on combating antisemitism.

The group, which says its mission is to single out those who promote “hatred of the U.S.A., Israel and Jews on North American college campuses,” listed the names of seven students and academics, including three current and former professors at Columbia University.

The seven people whom Canary Mission flagged, all of whom the group says could be deported because they are not U.S. citizens, are among thousands of people whose pictures, along with details of their alleged antisemitic activities, have been posted on Canary’s website since its creation a decade ago — all accused of anti-Israeli activism.

Since the Trump administration began targeting students in a sweeping immigration crackdown last month, nine students and professors, several of whom had engaged in protests or other activism over Israel’s war in Gaza, have been either threatened with deportation or detained. Three of them had appeared on the Canary Mission website.

The actions taken in recent weeks against these foreign students and academics, many of them highly accomplished in their fields, have raised questions about why federal authorities are singling them out, and what role outside groups like Canary Mission are playing in identifying targets for deportation.

In a briefing on Monday, a State Department spokeswoman, asked about whether such lists played a role in decision-making, said the agency would not discuss “what happens with individuals and visas, and whether they’re issued or if they’re revoked.”

The federal Immigration and Customs Enforcement agency has said that it does not rely on lists from Canary Mission, and some of the students who’ve been targeted by federal agents do not appear on any of the lists.

Yet some of them do. And immigration lawyers and experts point to coincidences that suggest to them that the information circulated by Canary Mission and another pro-Israel group, Betar, may be providing road maps for ICE enforcement actions.

Rumeysa Ozturk, a Turkish graduate student at Tufts University, learned in early March that her photograph and résumé had been posted on Canary Mission’s website, which claimed that she had “engaged in anti-Israel activism.”

It was an apparent reference to an opinion essay she had cowritten in the Tufts student newspaper, criticizing the university for not sanctioning Israel over the war in Gaza.

On March 25, federal agents detained Ms. Ozturk while she was walking about two miles from campus in Somerville, Mass. A video of the episode has gone viral, evoking comparisons to countries where those who express political dissent risk being jailed.

Details about Canary Mission’s leadership, origins and funding are murky, with a few exceptions.

The group has not sought tax-exempt status in the United States, meaning that, unlike most American nonprofit organizations, it does not file disclosure statements about its leadership and budget with the federal government. It also does not list a physical address.

News organizations have cited tax records showing contributions to the group from various Jewish foundations, and in 2021, Jewish Currents reported a $50,000 contribution from Michael Leven, a Jewish philanthropist who is the former chief operating officer of the Las Vegas Sands Corp., the luxury hotel and resort operator.

Mr. Leven told Jewish Currents at the time that he hoped to help “identify significant antisemites” and “bring the knowledge of their antisemitism to the surface.” While he paused his contributions at some point, he said in an email on Tuesday that his donations had resumed.

Canary Mission, asked if it had shared information on potential deportation targets with federal authorities, said that it had not. “Our investigations of anti-U.S. and antisemitic extremists are all publicly available on our website,” the group said in a statement.

Betar, though, has openly said it is distributing a “deport list” of 3,000 immigrants who it said had engaged in support for terrorism, with some names already submitted to government officials.

“We have provided thousands of names of jihadis to the Trump administration of visitors to America who support Hamas,” Betar said in a statement.

Betar is a 100-year-old Zionist organization that now claims 35 chapters worldwide. The group has been labeled extremist by the Anti-Defamation League, which said its research showed that Betar had adopted the far-right slogan “Every Jew, a .22,” openly embraced Islamophobia and harassed Muslims online and in person.

Betar denied the organization’s characterization, adding that it stood behind “the right of every Jew to defend themselves, their families and their communities.”

On March 13, Betar posted what it called a “deport alert” aimed at Momodou Taal, a British-Gambian graduate student at Cornell University who has also been targeted by ICE. Perhaps coincidentally, the State Department has said it moved to revoke Mr. Taal’s visa on March 14, the day after the alert was sent.

Mr. Taal posted on social media Monday that he had elected to leave the country, abandoning a federal court fight to remain.

Jonathan Wallace, a lawyer representing one of the seven “deportable” people posted on Canary Mission’s “Uncovering Foreign Nationals” web page, called the group a “predator in the ecosystem that we’re living in right now.” Critics say the lists amount to doxxing, the publishing of private information about someone with malicious intent.

“Unfortunately, a prime way of having ICE turn up at your door is if you’re being actively doxxed,” said Mr. Wallace, the lawyer for Mohamed Abdou, a former visiting professor at Columbia whose contract was not renewed last year.

According to documents filed in a lawsuit against Columbia, Dr. Abdou was doxxed by Canary Mission.

He was featured on the group’s recent list, which also included two graduate students who had already been targeted by immigration authorities before the list was published — Mahmoud Khalil, who was detained at his apartment near Columbia University on March 8, and Mr. Taal, whose visa was revoked.

The list of seven is just a tiny sampling of the more than 2,000 online dossiers Canary Mission has posted on its website, some dating back as far as 2015. Many of those listed are not immigrants, but American professors and students from across the country who have been active in campus protests against Israeli government policies. Several of those listed are Jewish.

Zachary Lockman, a New York University professor of Middle Eastern and Islamic Studies, sees the group as part of a broader campaign to discredit opponents of Israeli government policy, a movement that has gained steam since last year’s U.S. presidential election, the Oct. 7 attack on Israel led by Hamas and the subsequent war in Gaza.

“This has all been underway for decades,” Dr. Lockman said. “Obviously since Oct. 7, it’s escalated dramatically. And since Trump took office, they have the government on their side in a very active way.”

Andrew Ross, a New York University professor of social and cultural analysis, who has long been listed on the Canary Mission site, said the implications of inclusion could be enormous.

“If you find yourself on Canary Mission, you’re subject to a lot of harassment and intimidation and campaigns to have you fired,” he said. “Character assassination and death threats are pretty common. All of these things certainly happened to me over the years.”

The Canary Mission entries are frequently among the first things that pop up in a Google search of the names of those listed.

Dr. Lockman, who himself has been targeted by Canary Mission, said there could be serious consequences for some of those included on the list, particularly for students from Muslim backgrounds.

In 2018, the Middle East Studies Association, an academic group, published a report, “Exposing Canary Mission,” that compared the group’s tactics to the Red Scare of the 1950s, when the government targeted those purportedly engaged in Communist subversion. The report also accused the organization of “misinformation, omissions, quotations taken out of context and allegations based on guilt by association.”

In 2023, even before the Hamas attack on Israel, Erwin Chemerinsky, the dean of the law school at the University of California, Berkeley, issued a statement condemning the group. Noting Canary Mission’s stated intent to keep “today’s radicals from becoming tomorrow’s employees,” Dr. Chemerinsky wrote that its dossiers had “caused great injury to students and their community.”

Dr. Ross, the N.Y.U. professor who found himself on the Canary Mission site, said the pressure created by the doxxing could be so intense that some people had performed acts of contrition, posting repudiations of their past pro-Palestinian stances. He said this sometimes brought the relative relief of being moved to another of the group’s web pages and listed as an “Ex Canary.”

Anemona Hartocollis contributed reporting.