Belin was hired by Lee Rankin, chief counsel to the Commission, who assigned a team of two lawyers to each of the major areas for investigation.  Belin and Joe Ball, a criminal defense lawyer from Los Angeles, shared the important task of investigating Oswald’s activities during the assassination.  As their work progressed, Belin focused his efforts on trying to prove that a second shooter had participated in the assassination, but detailed work by the FBI and analysis of the Zapruder film suggested that all of the shots that hit President Kennedy and Texas Governor John Connally originated from Oswald’s position in the book depository.