NEW YORK – One of the people arrested at Columbia University in New York this past week was a middle-aged saxophonist who headed up to the campus from his Hell’s Kitchen apartment after learning about the pro-Palestinian protests on social media.

Another was tending his sidewalk pepper patch a few blocks from the student demonstrations when he learnt the police were moving in and, grabbing a metal dog bowl and a spoon to bang against it, rushed to the students’ aid.

A third had been active in other left-leaning protests across the city but also happened to work as a nanny nearby. She went to the university gates on April 30 and linked arms with other protesters in an unsuccessful attempt to thwart the advancing officers, she said.

After pro-Palestinian demonstrators occupied a building on Columbia’s campus last week, demanding that the university end all financial ties with Israel, the New York Police Department moved in and arrested more than 100 people there. New York City Mayor Eric Adams and other city leaders have accused so-called outside agitators – professional organisers with no ties to the university – of hijacking a peaceful student protest and spurring its participants to adopt ever more aggressive tactics.

“Professional, external actors are involved in these protests,” said New York City Police Commissioner Edward Caban. “They are not affiliated with either the institutions or campuses in question, and they are working to escalate the situation.”

A New York Times review of police records and interviews with dozens of people involved in the protest at Columbia found that a small handful of the nearly three dozen arrestees who lacked ties to the university had also participated in other protests across the US.

One man who was taken into custody while protesting inside Hamilton Hall, the occupied campus building, had been charged with rioting and wearing a disguise to evade the police during a demonstration in California nearly a decade earlier.

But the examination also revealed that far more of the unaffiliated protesters had no such histories. Rather, they said, they arrived at Columbia in response to word-of-mouth or social media posts to join the demonstration out of some combination of solidarity and curiosity.

There was little evidence to suggest they had helped organise or escalate the protests, and many were arrested without having ever set foot on campus.

Typical among them was Mr Matthew Cavalletto, a 52-year-old computer programmer who has lived within a kilometre of Columbia for most of his life. Mr Cavalletto, the gardener with the dog bowl, was arrested on the street outside Columbia after he stood in the middle of the intersection and refused to budge. He dismissed the notion that any outsiders were pulling the strings.

“I sort of had to laugh because I guess you could think of me as an outside agitator,” he said. “Not that far outside, like six blocks away, but, you know, almost outside.”

City officials have said that 29 per cent of those arrested at Columbia last week had no connection with the university. In a statement, a spokeswoman for Mr Adams said that the arrest numbers “speak for themselves”.

“To ignore these facts and solely blame college students for the escalation of violence and hateful rhetoric would be both reckless and misleading, and unfair to students who did want to protest peacefully,” spokeswoman Kayla Mamelak said.

Mr Adams has said that even a small number of outsiders can inflame tensions and cause protests to veer into violence. And as evidence that the campus has been infiltrated, he has pointed to the presence there at various times of 63-year-old career activist Lisa Fithian, and also noted the presence of Ms Nahla Al-Arian, the wife of a man who faced terrorism charges in Florida nearly 20 years ago. Her daughter was a graduate of Columbia’s journalism school.

Ms Fithian, who has written a book on protest tactics and charged money to run demonstrations and teach techniques for taking over the streets, was captured on video on April 30 apparently urging counter-protesters to step aside so that Hamilton Hall could be barricaded. She has denied playing any larger role in organising the Columbia protests.

Neither woman was present during the police sweeps on April 30.

Also present on April 30 – and arrested inside Hamilton Hall – was Mr James Carlson, 40, the protester previously arrested in California.

A lawyer, he was also accused of setting an Israeli flag on fire with a lighter at another protest outside Columbia’s campus  in April, court records show. Mr Carlson, an advocate for animal rights, appeared to have participated in a wide variety of protests over the years, including demonstrations related to Black Lives Matter, immigration policy and environmental causes, according to posts on social media.

His lawyer declined to comment. There was no indication Mr Carlson was involved in organising or leading the protests at Columbia.

For their part, student organisers of the protests and student participants who were arrested disputed the idea that they had been manipulated by outside actors.

“I think that these schools are quite scared in a way – and I think they’ve escalated to a degree that shows that they don’t have so many resources available other than, you know, kind of militarised action,” said 30-year-old graduate student Val Ly of Columbia’s architecture programme, who was arrested on a disorderly conduct charge.

“I want to make sure it’s very clear there were not ‘external agitators’, as far as I can tell, who were inside the building.”

Columbia has been a national focal point in one of the largest student protest movements in decades. Tensions over the war in the Gaza Strip have prompted a wave of student activism, resulting in the arrests or detainment of more than 2,300 people on campuses nationwide in the US.

The protests over Israel’s offensive in Gaza had been brewing at Columbia for months. But the situation escalated on April 18, when the university’s president, Ms Nemat Shafik, called on the police to enter the private campus and clear out a pro-Palestinian encampment. More than 100 students were arrested.

Ms Shafik’s decision led to more protests, both at Columbia and at campuses around the country. A new, larger encampment was established at Columbia. Fewer than two weeks after the police initially cleared the encampment, a group of protesters, shortly after midnight, took over Hamilton Hall and barricaded themselves inside.

Later that day, the police officers stormed the building through a second-floor window, rooted out the protesters and took others into custody on and around campus as well, making more than 100 arrests in all.

During a news briefing on May 2, Columbia’s vice-president for communications Ben Chang said figures supplied by the New York Police Department about those accused of occupying Hamilton Hall had confirmed the expectations of university leaders that many of the participants were not connected with Columbia.

“A significant portion of those who broke the law and occupied Hamilton Hall were outsiders,” said Mr Chang, who said the figures showed that 13 of the nearly four dozen people arrested in the takeover were not affiliated with Columbia.

But The New York Times’ review of police records revealed a slightly different picture, showing that just nine of those people had no apparent ties to the university. The rest were current or former undergraduate or graduate students or university employees, The New York Times found. It was not clear why the university’s numbers differed.

Overall, the records show, more than two-thirds of the demonstrators arrested on or near Columbia’s campus last week had some connection to the university.

As at May 2, 46 people arrested inside Hamilton Hall had been arraigned in court. They each faced one misdemeanour charge of trespassing, a spokesperson for the Manhattan district attorney’s office said. At their arraignments, prosecutors said they might pursue additional charges. They agreed that all arrestees should be released without bail.

The university has said students who occupied the building will face expulsion, and in a news briefing last week, Mr Chang said the university had begun suspending students who had not complied with an order to leave the encampment.

The claim that outsiders were whipping locals into organising protests has been a common refrain in past social movements and was levelled at protesters during the civil rights movement, according to Mr Aldon Morris, an emeritus professor of sociology and African American studies at Northwestern University.

“The outside agitator charge is in many ways a measure to delegitimise the protests and protesters,” Mr Morris said. “It is a weapon that exists for the police in terms of dealing with protests to stop protests, to stifle protests.” NYTIMES