In 1963, Frazier was a nineteen-year-old order filler at the Texas School Book Depository. He trained fellow employee Lee Harvey Oswald and drove Oswald to work occasionally, including on November 22, 1963. After witnessing the Kennedy assassination, Frazier was detained and questioned by Dallas police. He later testified at length before the Warren Commission, particularly regarding the package he observed Oswald carrying on the morning of the assassination. Recorded June 19 and 21, 2002, July 13, 2013, and August 9, 2021.