But at least nine of the 46 protesters arrested inside the barricaded Hamilton Hall on April 30 sustained injuries beyond minor scrapes and bruises, according to medical records, photographs shared by protesters, and interviews. The documented injuries included a fractured eye socket, concussions, an ankle sprain, cuts, and injured wrists and hands from tight plastic flexicuffs.

All of the 46 protesters arrested inside Hamilton were charged with third-degree trespass, a misdemeanor. The arrests came after Columbia President Minouche Shafik, in a hotly debated decision, called in police hours into the occupation at the epicenter of a student protest movement that has spread to campuses around the world. Other university officials across the country also have called in police to quell pro-Palestinian and anti-Israel protest camps.

Reuters shared details of the protesters' injuries and accounts with the mayor's office, New York police and Columbia. None disputed the injuries. The mayor's office and the police said officers acted professionally.

At least three injured protesters arrested inside Hamilton were taken by police to hospitals that night while still in custody, time-stamped hospital records show.

Other protesters, who are demanding Columbia divest from arms makers and other companies that support Israel's government, had their injuries documented by volunteer doctors who provide support to people arrested by police and met them outside moments after their release from custody on May 2. Some then sought medical attention at clinics.

"I was slammed downward to the ground and, when I turned my head to see if there were any comrades who needed assistance, an officer kicked me in the eye and I went straight down, and there was that buzzing and sharp ringing in the ears," said Christopher Holmes, a 25-year-old graduate student at the Columbia affiliate college Union Theological Seminary. Moments later, an officer slammed the left side of his forehead into the floor of Hamilton Hall, Holmes said.

His eye still swollen days after his release, a friend took him to a Manhattan hospital. Hospital records show doctors determined his eye socket was fractured and that he was concussed.

'WE ARE UNARMED!'

Kayla Mamelak, a spokesperson for the mayor, declined to say when the mayor first learned that protesters had been injured. At a May 1 press conference with police leaders, Adams said the arrests were "organized, calm, and that there were no injuries."

Mamelak wrote in an email that the arrests, which involved hundreds of armed officers in riot gear, were "a complicated operation" handled "with professionalism and respect."

A police spokesperson, who declined to give their name, also did not dispute the protesters' injuries, writing in an email that officers responded "swiftly, professionally, and effectively."

Both spokespeople declined to provide unedited videos from officers' body-worn cameras and use-of-force and injuries reports from the arrests. That night, police ordered students outside Hamilton into dormitories and forced journalists off campus.

Columbia spokesperson Ben Chang said he would answer Reuters queries by May 10, but did not send replies by that date and did not respond to subsequent emails and phone calls.

As police used electric saws to cut through barricades of heavy furniture and bike chains, several protesters said they sat on the floor in Hamilton's lobby, hands raised. Police threw in a flash-bang grenade, setting off disorienting loud bangs and bursts of light, before rushing through the doors.

Gabriel Yancy, a 24-year-old research assistant who has since been fired from his job in a Columbia neuroscience laboratory, said he watched officers throw some protesters to the ground, step on at least three protesters, and kick at least one in the torso.

Aidan Parisi, a 27-year-old student in Columbia's social work department, recalled police "stepping on top of people, throwing people," and said that several protesters yelled, "We are unarmed!"

Several students said officers knelt forcefully on their backs. New York City passed a law in 2020 prohibiting police from using knee restraints that compress the diaphragm.

Gideon Oliver, a civil rights lawyer who now represents some of the arrested students, was involved in a reform agreement that the New York state attorney general reached with the New York Police Department last year to end its "pattern of excessive force" against protesters.

"Now is the time for the city and for the police department to deescalate and to stop engaging in tactics on the streets that appear designed to chill protests," Oliver said.