Lawman, Kennedy Assassination Figure. As head of the Dallas Police Department’s Robbery-Homicide unit in 1963, he was Lee Harvey Oswald’s primary interrogator.  Law enforcement officers led by him interrogated Oswald over the less than 48 hours between his arrest and death. John Fritz was present for more of the questioning than any other officer.  Family links:  Parents:  Blake Fritz (1873 – 1924)  Ada Hamilton Fritz (1879 – 1959)  Spouse:  Alma Faye Turner Fritz (1922 – 2012)* *Calculated relationship