In 1972, the Kennedy family chose John K. Lattimer, MD, as the first nongovernmental expert to examine evidence taken at Kennedy's autopsy. Lattimer performed ballistic tests and other research to prove that Lee Harvey Oswald was likely the sniper who shot and killed President John F. Kennedy from the Texas School Book Depository in Dallas. Dr. Lattimer frequently performed a demonstration of Oswald's shooting, firing three well-aimed shots within 8.3 seconds with Carcano M91/38 and under the same firing conditions. By doing so Dr. Lattimer intended to prove that Oswald could have performed such a feat. He continued to perform this demonstration well into his late 80s. Lattimer owned Oswald's Marine shooting record which he said showed that Oswald was an excellent shot. In 1980, Dr. Lattimer wrote a book: "Kennedy and Lincoln: Medical & Ballistic Comparisons of Their Assassinations" in which he did an investigation of both the Lincoln and the Kennedy assassinations, and supported the findings of the Warren Commission. In his book, Lattimer theorized that President Kennedy's arms exhibited the "Thorburn Position" with elbows extended and arms folded inward, as a neurological reaction to the bullet wound to his spine.