Cal Poly Humboldt, which in the last week and a half has become the site of the "nation's most entrenched protest," per the New York Times, was the site of another show of force by police this morning in the nationwide campus protest movement.

Sheriff's deputies moved in around 2:30 am Tuesday and arrested some 35 protesters, as KCRA reports. The SF Chronicle separately reported that 30 individuals had been removed from the campus but were not arrested, and only 25 arrests were made.

"What was occurring was not free expression or a protest," the university said in a statement. "It was criminal activity, and there were serious concerns it would spread even further on campus."

There were an estimated 300 to 350 protesters gathered to protect the occupied building Monday night, per the Chronicle, and they faced an operation by some 300 law enforcement personnel in riot gear.

Unlike at many schools across the country where pro-Palestinian encampment protests have taken shape over the past two weeks, the protest at Cal Poly Humboldt — formerly known as Humboldt State — which began on April 22, included the occupation of two major buildings on campus. As one professor at the school, Anthony Silvaggio, who is also a former student there, tells the New York Times, "Because of the long history of activism [here], we recognize that putting a tent out in front of the building may not be as effective of a statement for a student protest [as occupying it]."

In response to the protest last week, the university suspended classes for several days, and on Monday the school announced that the campus would remain closed until May 10, one day before commencement is scheduled. The administration strongly urged protesters to leave Siemens Hall, the building they had forcibly taken over a week earlier, which is also home to the office of the president of the school and other administrative offices.

The protesters later took over a second adjacent building in order to use its bathrooms and meeting spaces.

Video below posted to Facebook shows a tour inside the now defaced Siemens Hall, whose walls have been covered in graffiti, and which has been renamed in chalk on its exterior "Intifada Hall." You can also see one student carrying a sign out of the building that says, "Help Us Please They Are Going to Attack."

After the late night/early morning operation at the campus, Humboldt County Sheriff William Honsal said it was "essential to reestablishing order on campus."

"By restoring order, we've sent a clear message that the criminal and dangerous activities we experienced were not peaceful protests, but outright criminal behavior, which is unacceptable," Sheriff Honsal said.

Students and staff arrested could face campus discipline, but they also face criminal charges including unlawful assembly, vandalism, conspiracy, and assault on police officers.

The school, 275 miles north of San Francisco in a coastal redwood grove is often associated with pot-smoking hippie vibes as well student activism. Responding to state funding issues, university president Tom Jackson Jr., a veteran of the U.S. Coast Guard Reserve, pivoted the school in 2022 into the state's polytechnic university system, becoming one of just three Cal Poly campuses in the state focusing on STEM disciplines. That pivot came with a cash infusion of $458 million, which was welcome amid a period of enrollment decline, as the Times reports.

One of the most notable protests in Humboldt County was the 1990s tree-sitting protest of activist Julia Butterfly Hill, who was part of a movement protesting against the logging of redwoods. Hill lived in a redwood tree she had named Luna for 738 days, from December 1997 to December 1999.

In an echo of that protest, a Humboldt student took up residence in a redwood tree over the weekend near the quad where the occupied buildings stand, displaying signs that said "Free Gaza" and "End Empire," as the Times reports. As one graduate student told the paper, that gesture "indicates that there’s a desire for a much longer occupation."

Students and faculty have noticed that Jackson, who has served as university president since 2019, has taken a more hard-line approach to protests. And while student activists were told last week that if they left Siemens Hall they would not face immediate arrest, Jackson appeared to have lost patience by Monday.

In a statement following the arrests, Jackson said, "This is a difficult day, it breaks my heart to see it, and truly nobody wanted to see things come to this."

It is unclear if the campus will now reopen earlier than May 10, or how any remaining protesters who were not arrested may react.

The university estimates the damage to Siemens Hall to be in the millions.

Related: 'Gaza Solidarity Encampment,' Like the One at Columbia University, Established at UC Berkeley