Nazi hunting sounds like an admirable activity, especially when your target is a senior officer in the Waffen SS, which the Nuremberg trials declared a criminal organization complicit in the Nazis' worst crimes. So if you're a Nazi hunter you'd probably be excited to stumble onto Bernhard Frank, a 97-year-old German man who worked in the upper echelons of the SS, including as an aide to SS chief Heinrich Himmler. Amateur hunter Mark Gould, an American, was certainly excited. But did he go too far?

The New York Times' Michael Slackman reports on Gould's obsessive quest to expose Frank's Nazi past. The elderly former Nazi is certainly far from a saint, having spent years in Himmler's office, which was involved in many of the Nazis' worst crimes, and telling Gould in a conversation the American secretly taped that the Jews "dug their own grave."

But there are some problems with this Nazi hunt, which culminated this weekend with Gould filing a lawsuit against Frank for allegedly ordering Ukrainian civilians to be killed and having, as Slackman puts it, "facilitated the machinery of Nazi death." (Gould also told Frank, "You'll be dead soon.") First, Frank's history is hardly a secret: he has published an autobiography and appeared on German TV to discuss his past. Second, German Nazi investigators  and Holocaust experts say there is no evidence Frank was involved in war crimes.

Gould, it turns out, may not be the most reliable investigator or historian. His lawsuit, according to the Times, appears to be based on a questionable story alleging his ancestors were killed in Ukraine in 1941. He has spent years collecting Nazi memorabilia and posed as a neo-Nazi to get close to Frank. While the story doesn't portray Frank in a positive light, Gould doesn't come out as a hero either.

But Gould's odd tactics and questionable motive aside, the question remains: What does it mean for a Nazi to be "guilty"? Bernhard Frank doesn't deny his years as a high-ranking member of the Nazi Party's most brutal agency. But that in itself is not illegal. Gould, however, lied to, spied on, and ultimately threatened the near-centenarian. Could it be that, in this case, it was the Nazi hunter, and not the hunted Nazi, who has committed the crime?