This is the shocking moment a black Northwestern University PhD student was tackled to the ground when police thought he’d stolen the car he was driving. Lawrence Crosby is now suing the Evanston Police Department for excessive force and false arrest following his confrontation in Chicago in October 2015.Authorities released dashboard video recordings on Wednesday of the moment Crosby, then 25, was pulled over for a traffic stop and subsequently beaten and cuffed. Footage shows police signalling for Crosby to stop in the 1500 block of Ridge Avenue in Evanston about 7pm on October 10, 2015.He can be seen getting out of his Chevrolet with his arms in the air before telling officers he owns the vehicle. Crosby, who was studying for his doctoral degree in civil engineering, repeatedly told the officers he owned the car and had the documentation to prove it. When police eventually realized Crosby did own the car, the student was charged with disobeying officers.