City Heat (1984)

Kansas City in the 1930s: Private Investigator Mike Murphy's (Burt Reynolds') partner is brutally murdered when he tries to blackmail a mobster with his secret accounting records. When a rival gang boss goes after the missing records, ex-policeman Murphy is forced to team up again with his ex-partner Lieutenant Speer (Clint Eastwood), even though they can't stand each other, to fight both gangs before Kansas City erupts in a mob war.