America's quirkiest documentarian, Errol Morris ("The Thin Blue Line", "A Brief History of Time"), tackles an unusual and highly provocative subject--that of Fred Leuchter Jr., an expert in "humane executions" who became a dupe for neo-Nazis. But the film doesn't amount to much. Introduced in the film's first half-hour, Leuchter is revealed as a sincere, oblivious sort who is making a living advising various state prisons on how to improve the quality of their electric chairs and systems of lethal injection so that the prisoners who are executed don't suffer. But then he is commissioned by notorious Toronto Holocaust denier Ernst Zundel to go to Auschwitz and "prove" that it could never have been used as a gas chamber to kill hundreds of thousands of Jews. The rest of "Mr. Death" details what happened to Leuchter as a result of that trip. Morris provides plenty of evidence that Auschwitz was indeed a killing field, but his linkages in the film are suspect. Like Morris, many will connect Leuchter and his blathering about how to best to execute a man with the Nazis and their genocidal ways. But that's facile; you could just as clearly argue that proponents of capital punishment genuinely want to see justice served, a concept that has nothing in common with anything the Nazis did during their reign. And Leuchter, while interesting at the outset, is finally revealed as a fool who has little insight to offer about anything he's done. "Mr. Death" has none of the underlying power of "The Thin Blue Line," which actually freed a man from jail. At best, Leuchter's tale might have made for a decent "60 Minutes" segment. Stretched to a feature, it's Morris' most pointless film. Starring Fred A. Leuchter Jr. Directed by Errol Morris. Produced by David Collins, Michael Williams and Dorothy Aufiero. Documentary. A Lions Gate release. Not yet rated. Running time: 96 min.