I wrote to the Library of Congress some time ago about how Hitler supporters continued killing our soldiers at the end of WWII. They didn't have the number of soldiers killed by the insurgency, but on the History Channel both my husband and I thought it numbered in the thousands.
Their favorite method was to string barbed wire across the road which beheaded soldiers as they drove by. Then our soldiers put wooden crosses on the front of jeeps and other methods were employed.
Thousands? Perhaps a couple of dozen at most, and most of these were by criminal gangs. The pro-Iraq war crowd was touting the werewolf insurgency a few years ago but dropped it after it was proved that there was "no there, there." There was no post-war "insurgency" in Germany.