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.

Tension had been building at Princeton University as pro-Palestinian demonstrators occupied a white-columned, Greek Revival-style building at the center of campus and the police moved in. An angry crowd had surrounded a bus where two demonstrators were being held after officers led them out of the building.

“It was a tense time as there were hundreds of protesters that were attempting to interfere with lawful arrests,” reads a police report from that day, April 29, 2024.

David Piegaro, then a Princeton junior, was there filming with his phone. Mr. Piegaro says he was not one of the protesters, and he opposes much of their language and tactics. He described himself as a pro-Israel “citizen journalist” who was concerned by what he saw as the university’s insufficient response and wanted to bear witness by recording.

By nightfall, he was one of more than a dozen students charged with wrongdoing at the elite New Jersey school. He joined the roughly 3,100 people arrested or detained last spring on campuses across the county amid a wave of student activism over the war in Gaza.

Trespassing charges are pending against the pro-Palestinian demonstrators arrested at Princeton that day. But Mr. Piegaro, who was charged with assault, is so far the only person to have stood trial. A municipal court judge who presided over the two-day proceeding in February is expected to announce a verdict on Tuesday.

The Trump administration has made a dramatic show of punishing or trying to punish college-age protesters who have spoken out against Israel’s military response in Gaza, where the death toll has surpassed 50,000 people.

The administration has either detained or threatened to deport at least nine international students or faculty members, including a Tufts University graduate student who had co-written an opinion piece in the student newspaper criticizing the university’s response to pro-Palestinian demands. She was taken into custody last week.

But the arrest and trial of Mr. Piegaro, who was born and raised in New Jersey, underscore the complexity of the issues facing university administrators and the police as they strive to balance respect for free expression with questions about what constitutes hate speech.

Mr. Piegaro, 27, is older than most undergraduate students. He began studying at Princeton after serving for several years in the U.S. Army, where he worked as an intelligence analyst with a top-secret security clearance.

He is Jewish and said he was troubled by the deadly attack on Israel by the terror group Hamas, which killed about 1,200 people, and the tactics of the growing pro-Palestinian movement on campus.

He said he was not, however, involved in the protests or counterprotests. And one of the charges brought against him — aggravated assault — was far more serious than the trespassing citations filed against 13 other Princeton students charged that day.

As Mr. Piegaro’s case has moved through the criminal justice system, three of the charges he initially faced, including aggravated assault, were dropped or reduced. He and his lawyer, Gerald Krovatin, said he twice refused offers to plead guilty to a lesser charge, convinced of his innocence and unwilling to voluntarily mar his record with a conviction of any kind.

He went to trial on a lower-level assault charge, equivalent to a misdemeanor, that carries a potential penalty of six months in jail and a $1,000 fine.

“I really believe I’m the victim,” Mr. Piegaro said in an interview. “I really don’t think I did anything.”

The run-in that led to his arrest involved the head of the school’s campus security department, Kenneth Strother Jr.

Mr. Piegaro, upset that more than a dozen of the protesters had been released with citations, had begun recording two of their faculty advisers, who were speaking with Mr. Strother and walking toward Whig Hall, a building adjacent to Clio Hall, the one that had been occupied.

Mr. Strother barred Mr. Piegaro from trying to follow them in, and Mr. Piegaro can be heard on the video he recorded asking Mr. Strother, who was not in uniform or wearing a badge, his name and position.

“Don’t touch me,” Mr. Piegaro says before the video abruptly ends. Seconds later, he says, he was tumbling down the front steps of the building.

What happened in between is the crux of the dispute.

According to Mr. Strother, whose account appeared in the police report, Mr. Piegaro “pushed himself” into Mr. Strother, who “grabbed Mr. Piegaro by his arm and told him he was under arrest.” Mr. Strother said that he lost hold of Mr. Piegaro, who was resisting arrest, causing Mr. Piegaro to fall down the stairs.

Mr. Piegaro says he was the one who was assaulted.

Sarah Kwartler, a graduate student who had gone on two dates with Mr. Piegaro several years ago and recognized him, testified that she stopped to watch part of what unfolded.

She said she saw Mr. Strother holding Mr. Piegaro “like an open pair of scissors,” losing his grip and dropping him, according to a summary of the testimony submitted to the judge. Mr. Piegaro then rolled to the bottom of the stairs, Ms. Kwartler said, where he was handcuffed and arrested.

Complaining of soreness, Mr. Piegaro was taken to a hospital and evaluated for broken ribs and a concussion. Mr. Strother, who did not reply to requests for comment, was uninjured, according to the police report.

Mr. Krovatin, Mr. Piegaro’s lawyer, has argued that the decision to initially charge his client with aggravated assault, in addition to several other crimes, smacks of disparate treatment when compared with the lower-level trespassing charges leveled against the protesters.

“The fact remains that the only student charged with three indictable offenses on that day was a Jewish U.S. Army veteran,” Mr. Krovatin said, adding, “I don’t get why Princeton hasn’t pulled back on this.”

A spokeswoman for Princeton, Jennifer Morrill, said that the university deferred to the judgment of the municipal prosecutor and the municipal judge. She drew a distinction between Mr. Piegaro’s assault case and the trespassing charges filed against the protesters.

With regard to the trespassing charges, she said, “The university is not a party to — and has not intervened in — those court proceedings, though the university has consistently said that it supports an outcome that would minimize the impact of the arrest on these individuals.”

She added, “The university has no comment on the separate charges filed against an individual in connection with his interaction with a police officer.”

Two of the pro-Palestinian demonstrators arrested at Princeton last April declined to comment. Princeton’s municipal prosecutor, Christopher Koutsouris, did not return calls or emails.

Mr. Piegaro said that after he was arrested, he was barred from student housing and from campus for about two weeks. He spent a few days living with Rabbi Eitan Webb, a Jewish chaplain and director of Princeton University’s Chabad House.

Rabbi Webb, in an interview, recalled a “pressure-cooker effect” on campus last spring.

“In that environment, speaking specifically to the events of that day, when you have a whole host of public safety officers, administrators — I think doing their best — it’s not surprising that mistakes would get made,” Rabbi Webb, who attended Mr. Piegaro’s trial, said.

He said he believed that the testimony showed that Mr. Piegaro was “not guilty.”

Breh Franky, who works in Princeton’s public safety department, testified that Mr. Piegaro had made contact with Mr. Strother as the student “charged the door,” according to the summary of the testimony.

But Zia Mian, one of the two faculty advisers who was speaking with Mr. Strother during the confrontation, testified, “This was not an attempt to attack the chief.”

Unlike many universities, Princeton quickly quashed efforts last April by pro-Palestinian demonstrators to erect tents on campus. At least two people were charged after they refused to take down tents. The takeover of Clio Hall on the night Mr. Piegaro was arrested lasted only about two hours after students were given a deadline to exit and told that they would face arrest.

The school has also managed to avoid much of the turmoil that has engulfed the presidents of several other prominent universities, including some who were summoned to testify before Congress about their schools’ responses to antisemitism on campus.

Ms. Morrill said that Princeton’s “expansive commitment to free speech — which includes peaceful dissent, protest and demonstrations — remains unwavering,” while noting the school’s rules governing the time, place and manner of such demonstrations. And the campus continues to bustle with signs of vigorous academic debate.

On Wednesday afternoon, the school is holding a forum on academic freedom and “whether, when, and how universities should take institutional stances on social and political issues.” Later this week, a conference is set to take place on the history, theory and politics of the “anti-Zionist idea.”

Keith A. Whittington, a longtime Princeton professor who is teaching this year at Yale Law School, is one of three academics participating in Wednesday’s forum. Professor Whittington, a free speech scholar, was on Princeton’s campus the day the pro-Palestinian demonstrators occupied Clio Hall but did not witness Mr. Piegaro’s arrest.

“It just sort of indicates how fraught things are on campuses, and how volatile these situations are,” Professor Whittington said.

In the moment, he said, facts can be difficult to parse.

“That’s why you have trials,” he said.

The University of Minnesota graduate student who was detained by immigration agents last week had not participated in campus activism or been outspoken about political issues, according to a lawsuit he filed on Sunday in federal court challenging the legality of his arrest.

Instead, the issue that appears to have put the student, Dogukan Gunaydin, on the radar of Immigration and Customs Enforcement is more mundane: a 2023 drunken-driving case in which he pleaded guilty.

After the university disclosed in a statement Friday night that a student had been taken into immigration custody, there was rampant speculation that the incident was related to pro-Palestinian activism, as has been the case at several other universities. Top elected officials, including Gov. Tim Walz of Minnesota and members of Congress, issued statements expressing concern, and students held protests on campus.

But no evidence of activism emerged in the case of Mr. Gunaydin, 28, a Turkish citizen who was pursuing a master’s degree in business administration. In an emailed statement, the Homeland Security Department said that Mr. Gunaydin had been arrested after the State Department revoked his visa over the D.U.I. case. “This is not related to student protests,” the statement said.

Immigration lawyers and other experts say they worry that the detention may signal a new front in the Trump administration’s approach to immigration enforcement.

The government routinely revokes student visas over criminal cases, but typically the holder has the opportunity to challenge the revocation with the help of a lawyer, or is allowed to leave the country voluntarily.

Mr. Gunaydin’s case was different. Another puzzling fact, according to the lawsuit, was that a computer system did not show his visa as revoked until several hours after he was taken into custody Thursday morning.

Starting in 2015, the State Department issued guidance making clear that a drunken-driving arrest could be grounds to revoke a visa. Since then, according to Debra Schneider, an immigration lawyer in Minneapolis, many foreigners working or studying in the United States have received letters notifying them about the revocation of a visa after a run-in with the law.

Yet, Ms. Schneider said, people on temporary work and student visas often manage to get visas reinstated, particularly if the circumstances of their cases are not egregious.

“I have never had someone put in custody by ICE over a D.U.I.,” she said.

In an emailed statement, the State Department said it would not discuss Mr. Gunaydin’s case, citing privacy considerations. But the department said: “The United States has zero tolerance for noncitizens who violate U.S. laws. Those who break the law, including students, may face visa refusal, visa revocation and/or deportation.”

Hannah Brown, Mr. Gunaydin’s lawyer, did not respond to requests for comment on Monday.

Mr. Gunaydin was taken into custody at approximately 9:30 a.m. Thursday after he stepped out of his St. Paul, Minn., residence to head to class, according to the lawsuit. The immigration agents drove him to the ICE office in St. Paul, where officials told the student that his visa had been “retroactively revoked,” according to the lawsuit.

“Mr. Gunaydin feared he was being kidnapped,” the lawsuit said, adding that officials provided no information on why the visa had been revoked.

That afternoon, roughly seven hours after Mr. Gunaydin was taken into custody, the online government registry of international student visa information showed that his visa had been revoked, according to the lawsuit. The system did not provide a clear explanation for the revocation but listed him as having failed to maintain legal status.

That evening, Mr. Gunaydin was told that he would be seeing an immigration judge on April 8, and he was later booked into the Sherburne County jail, which is roughly 35 miles northwest of downtown Minneapolis.

It was not clear on Monday whether Mr. Gunaydin had been formally placed in deportation proceedings.

His lawsuit lists President Trump, Secretary of State Marco Rubio and several senior officials at Homeland Security as defendants. The suit also seeks Mr. Gunaydin’s release from custody, arguing that his arrest violated his constitutional right to due process, as well as administrative law, because his visa was still valid when immigration agents took him into custody.

Carl C. Risch, who oversaw visa matters for most of Mr. Trump’s first term as an assistant secretary of state, said officials revoked visas as a result of arrests with “great frequency” over the years. But he suggested that it was unusual for agents to detain an international student over an old D.U.I. case without warning.

Mr. Risch, who is now in private practice at Kurzban Kurzban Tetzeli & Pratt, said federal authorities would historically have sought to detain “someone who was considered to be a danger to the community, perhaps somebody with a very serious or concerning criminal background, ties to terrorist organizations.”

If the government starts regularly detaining and deporting visa holders over misdemeanors like drunken-driving, Mr. Risch said, that would constitute a “change in policy, an escalation.”

On Monday, the president of another Minnesota school — Minnesota State University, Mankato — revealed that a student there was also taken into ICE custody last week.

The president, Edward S. Inch, said that no reason was given for the arrest on Friday. He said in a statement that he had reached out to state and federal officials “to share my concern and ask for their help in curbing this activity within our campus community of learners.”

The statement neither identified the student nor provided details of the events leading up to the arrest.

Mr. Gunaydin was arrested on June 24, 2023, after a Minneapolis police officer described seeing a car maneuver erratically around 1:50 a.m., according to a charging document. Mr. Gunaydin told the officer that he had drunk vodka earlier that evening, according to the document. A breathalyzer test showed that he had an alcohol blood level of 0.17 percent — well over the 0.08 percent legal limit to drive.

In March of last year, Mr. Gunaydin pleaded guilty to driving while impaired, a misdemeanor, according to court records. A judge ordered him to perform community service, attend a D.U.I. clinic and refrain from future traffic violations.

After the conviction, the lawsuit said, Mr. Gunaydin was admitted into business school and awarded a scholarship.

“He has maintained a full course load with a high G.P.A. and served in the M.B.A. Student Association,” according to the lawsuit.

Ana Ley and Stephanie Saul contributed reporting.