As hundreds of protesters gathered Friday at the University of Chicago to criticize the shooting of student Charles Thomas by a campus cop, nationally recognized experts in the use of force by police said videos show the officer did practically everything correctly.

Thomas, 21, a fourth-year political science student, was wounded Tuesday night after he charged the officer.

Thomas was holding a long metal object, which police at the scene thought was a crowbar. University officials have said it was a pipe; the police report refers to it as a tent stake.

Thomas’ mother says he never exhibited mental-health issues, although the family has a history of bipolar disorder.

“Based on our investigation, including interviews, we believe alcohol and/or marijuana may have been factors,” said Anthony Guglielmi, a spokesman for the Chicago Police Department, which is investigating whether the officer was legally justified in using deadly force.

“We are awaiting the results of toxicology tests,” Guglielmi said. “We are also exploring whether his mental health was a factor.”

Thomas faces felony charges of aggravated assault of a police officer and criminal damage to property for smashing the windows of two cars and two homes before his encounter with the police.

Thomas was a member of the school’s varsity rowing team. His friends have told the Sun-Times that his behavior Tuesday was out of character, with one saying he “wouldn’t hurt a fly.”

Activists gather in front of the University of Chicago’s Booth School of Business building to protest the shooting of student Charles Thomas. | Tyler LaRiviere/Sun-Times

Demonstrators met on campus Friday to call for stronger oversight of the 40-year-old campus police department.

“They are more willing to shoot students during a mental health crisis than de-escalate,” said Julie Xu, a fourth-year student, in a letter to the editor of the school newspaper, The Chicago Maroon.

But two national experts in the use of force by police said they reviewed video released by the university and believe the officer acted properly when he fired his weapon.

RELATED: Roommate: U of C student went to counseling weeks before he was shot by cop

A dashboard-camera video from the officer’s squad car and a video from a body camera he wore show he was aware from the onset that Thomas was in mental distress in an alley in the 5300 block of South Kimbark.

University of Chicago student Charles Thomas with friend Olivia De Keyser. | Olivia De Keyser photo

The officer, who joined the campus police force in January 2016 and had received 40 hours in crisis intervention training, addressed Thomas as “sir” as the student approached. The officer kept stepping backward as someone yelled “he’s got a crowbar!”

The officer shouted “put the weapon down!” as someone said “Tase him!” But Thomas didn’t drop the metal object and charged the officer, who screamed “don’t come at me!” before firing one shot at Thomas, striking him in the left shoulder.

David Harris, a law professor at the University of Pittsburgh, stressed the officer and his colleagues attempted to de-escalate the situation by moving away from Thomas instead of charging him.

“A less-than-lethal weapon, such as a Taser, is only appropriate when it could definitely stop a threat,” Harris said, adding that it’s inappropriate to use “when a lethal threat is being made.”

“While the weapon here looks like a crowbar, with the man advancing quickly toward the officer, that object could cause serious injury or even death. So I don’t anticipate a court would find the officer at fault for shooting.”

He cautioned that the video only offers one perspective, “so it is not a definitive account of everything involved.”

David A. Klinger, a professor of criminology and criminal justice at the University of Missouri at St. Louis, also viewed the video and found that the officer acted appropriately.

Klinger, a former cop in Los Angeles and Redmond, Wash., said he noticed the officer gave calm instructions to Thomas and used courteous language, addressing him as “sir.”

“The officer showed great restraint,” Klinger said.

He agreed with Harris that a Taser would not have been a proper choice in the situation because Thomas was moving, and the barbs that a Taser fires to deliver an incapacitating electrical jolt might not have struck him.

Still, the officer created a “tactical dilemma” by backing up so far that the “the officers the subject walked past are in the shooting officer’s background.” In other words, when the officer fired his weapon, he risked shooting the officers who were standing behind Thomas.

“But I have nothing to criticize these officers for,” Klinger said.

Contributing: Andy Grimm