Hundreds of students and staff gathered at the heart of McGill's downtown campus Monday to denounce the police action that led to four arrests during a student demonstration Thursday.

Members of the McGill community came together Monday to discuss the troubling force with which students were handled.

Students claim protesters had been roughed up by campus security during a tuition-fee demonstration as they tried to occupy the president's office.

The protesters formed a human chain outside the administration building, explained arrested student Ariel Prado.

"(It was) to prevent anyone from coming out or going in until we had news from the students who were locked inside the building," said Prado.

McGill security then called on Montreal police to intervene.

"The police showed up, and I was torn away from the chain, arrested for refusing to leave the campus and charged with assaulting a police officer," said Prado, who denies the assault. The charges against him have been dropped.

Amateur video posted online shows several examples of the police clashing with protesters.

"I got out of it before they started using tear gas and pepper spray," said student Eli Freedman, who attended Monday's event.

McGill's principal, Heather Munroe-Blum, said she wasn't on campus when the event occurred, but promises the university will investigate.

"Certainly having a major protest of tens of thousands of people on the border of our campus in response to tuition fees had some interaction with what happened on Campus on Thursday," she said.

McGill is now working with students to assist them in filing complaints against the Montreal police if they choose to do so.

McGill's dean of law will be conducting an investigation into the events Thursday, and is set to publicly release a report on Dec. 15.

Member of McGill's administration also showed a united front with the students by attending the rally Monday.

"We had a promise of a quiet gathering and we're here to be part of this," said deputy provost Morton Mendelson.

Student Isaac Gielen said the support seen at the rally is encouraging.

"Simply seeing everyone in support of the students like myself who were tear gassed on Thursday night, it's good to know you're not alone on your own campus," he said.

Gielen's mother, Mary Gratton, travelled from Belleville, Ont. to lend another voice to Monday's rally.

"I felt that I had to be here not only in support of the kids, but if anything similar happened again, I wanted to be witness to it," she said.