From 1975, Kansas City Massacre is Dan Curtis's 2nd made-for-tv movie based mainly around the FBI agent Melvin Purvis & the famous gangsters of the 1930s. John Karlen plays the role of Sam Cowley, whom worked closely beside Purvis. Interestly, in the previous film: Melvin Purvis G-MAN, John appears as a different character: 'Tony' Anthony Redecci, and Sam is played by Steve Kanaly instead.