Const. Christian Dobbs has been charged with assault causing bodily harm after the SIU learned of the incident through a story published in the media in March of this year.
The SIU investigates cases of serious injury, death, or sexual assault where police are involved.
At approximately 1:30 a.m. ET on April 12, 2010, police arrested Rudolph Raymond Costain on King Street East, the SIU said in a press release.
"During the arrest process, he was struck a number of times by an officer," the SIU said, noting that the 30-year-old was taken to St. Michael's Hospital where he was treated for head injuries.
The officer will appear before the Ontario Court of Justice in Toronto on July 17, 2013.