A Toronto police officer has being acquitted of assaulting an anti-poverty demonstrator at a loud rally four years ago that was captured on videotape.

A jury also found 48-year-old Const. Amar Katoch not guilty of perjury and attempting to obstruct justice by trying to fabricate evidence. The verdict was returned late Thursday night after six hours of deliberations.

Katoch, a 17-year-veteran, was charged after punching Alex Levant at an affordable housing protest near the Don Jail in November 2003.

Levant, a 36-year-old professor at Wilfred Laurier University, was then charged with assaulting police and obstructing justice.

Hundreds of demonstrators had gathered at the event, and the force warned officers there could be violence.

Levant testified there was a commotion near him, and as Katoch walked past him, the constable shoved him for no reason.

Levant said he approached Katoch to ask him why he assaulted him. When Levant placed his hand on the officer's arm to get his attention, the constable punched him in the face and tackled him.

Katoch charged Levant with assault and attempting to obstruct police while another officer was arresting someone else.

The Crown, however, dropped the charges against Levant on the second day of his trial after the defence presented a video of the incident that had been captured by a Ryerson student.

The tape, played in court and released to the media on Friday, shows Levant being peaceful before he was shoved and punched by Katoch.

The constable was then charged with assault and accused of altering his notes and lying on the witness stand.

While the video shows the assault, Katoch's lawyer said the few seconds of footage doesn't accurately reflect the hostile, noisy and confusing environment the officer found himself in.

"The video really doesn't show what you think it shows," Harry Black told CTV News.

"This was a case about an officer making an honest mistake in misidentifying two faces -- neither of which he had ever seen in his life before -- in less than 0.4 seconds."

On the obstruction of justice and perjury charges, Black said his client "genuinely believed he told the truth, there is no question about that."

The incident has been trying for Katoch and his family, Black said.

Katoch will return to full duties as a bike officer patrolling downtown streets.

The acquittal of a Toronto police officer was the second this week. On Wednesday, a judge found Const. Joseph Green not guilty of sexually assaulting a dancer at a downtown strip club.

With a report from CTV's Chris Eby