What started as a walk to the park with his dogs ended with a trip to the hospital for a Denver dog owner. 32-year-old Mark Ashford says he was beaten black and blue by two Denver Police officers."They punched him and pinned him up against the fence and forced his head into the concrete." Ashford's attorney, Will Hart, said the beating that was caught on camera is a clear case of Excessive Force. "This happened when he was walking his dogs, he has a conversation with another citizen that the police officer doesn't like and as a result, he ends up in the hospital," said Hart.Hart says Mark Ashford was walking his dogs near 20th and Little Raven in LoDo, when he saw police pull over a driver for failing to stop at a stop sign. Ashford told the driver he saw him stop and would be willing to testify in court. Hart says the officer overheard him and "wasn't very happy."That's when Ashford says the Denver police officers demanded his I.D. and detained him. Ashford tried to take a picture of the officers to document the incident, and a few second later he was on the ground.Police charged Ashford with interference and resisting arrest. Hart says, the charges were later dropped because the officers violated Ashford's 4th amendment rights, "they had no reason to stop him, take his ID or detain him."An Excessive Force complaint was filed against both officers involved. A Denver police spokesperson says the internal affairs department has completed its investigation, but they are now turning the case over to the independent police monitor. Police won't say if the officers were disciplined in any way until the investigation is complete.