"The video is disturbing," Victoria Middleton with the South Carolina ACLU said. "The investigation needs to thoroughly probe the appropriateness of the police actions. We question whether there could be any justification for releasing the K-9 in a situation like this. "
The video shows law enforcement officers removing McManus from his truck and striking him. McManus is on the ground when the K-9 approaches him.
The chase happened on Tuesday January 31st when McManus failed to stop for county Sheriff Al Cannon's lights and sirens on Highway 17.
On Wednesday, Cannon called a press conference to admit he had slapped and cursed at the suspect while McManus was handcuffed in the back of a police cruiser.
Check back with ABC News 4 as we continue to develop this story.