Mr. Death: The Rise and Fall of Fred A. Leuchter, Jr. 1999 on netflix

A portrait of the life and career of the infamous American execution device designer Fred A. Leuchter, Jr. Mr. Leuchter was an engineer who became an expert on execution devices and was later hired by holocaust revisionist historian Ernst Zundel to “prove” that there were no gas chambers at Auschwitz. Leuchter published a controversial report confirming Zundel’s position, which ultimately ruined his own career. Most of the footage is of Leuchter, working in and around execution facilities or chipping away at the walls of Auschwitz, but Morris also interviews various historians, associates, and neighbors.