A student said to have been out of control and delusional before he was beaten by police during a violent arrest at the University of Western Ontario doesn't remember what happened, his father said Friday.

Merzuk Zeljkovic said he was unable to explain what had sparked the incident involving his son Irnes, which was captured on video and viewed by tens of thousands on the internet.

"I don't know what's happened," his father told The Canadian Press. "Irnes [does not] remember. I'm upset."

Irnes Zeljkovic, 22, visited the family doctor Friday and plans to talk to a lawyer, his father said.

The video shows several officers pummelling the student in a London campus building hallway, prompting a wide range of reaction — from severe criticism that excessive force was used, to support for the police action.

During the 90-second clip, police are seen kneeing the student aggressively in the torso, repeatedly beating him on the back with batons and punching him.

Shocked and tired

His mother, who asked that her name not be used, said her son was "still shocked" and tired, and just wanted to sleep.

She also said she had no idea what prompted the incident, saying she was waiting until he was in better shape to try to figure out what had happened.

"I don't know, really. All of us are all so shocked. I have no idea," she said in a phone interview. "We just need time."

She said her son had some injuries from the arrest, but she couldn't describe them.

"I can't talk now. I'm sorry. I'm so stressed and shaking," she said.

Elgin Austen, director of campus police, said his officers were initially called after a delusional student, believing himself to be a professor, barged into an eighth-floor office and tried to evict its occupant.

"He thought he was somebody else. He didn't recognize his position or where he was — he thought he was a professor at Western and he named a professor," Austen said in an interview.

Student 'resisted arrest'

The 220-pound fourth-year student was "hyped up" and resisted arrest and efforts to calm him before city police, who arrived within minutes, used force to subdue him, said Austen, a former deputy chief of operations at London police.

Police said they had no prior contact with Zeljkovic.

"He must have been a good student or we would have had contact with him and we haven't," Austen said, adding this was the worst such incident he had seen in more than six years as campus police head.

"Something has happened more recently in his life to create this situation."

Toxicology tests were being done to see whether the student was under the influence of drugs, although alcohol was not involved, police said.

Despite criticism from some who had viewed the video, Austen said it's not surprising some viewers would have misinterpreted what they saw.

"Once they hit YouTube and other areas like that, the thing takes off and has a life of its own," Austen said.

"People judge based on what they saw, and some people at least become instant experts."

He said the crowd of people who witnessed the arrest first-hand did not interfere with police.

Police are completing their investigation, reviewing the use of force and making counselling available to those affected, including Zeljkovic and his family.