On Friday, March 31, 1922, Maria Baumgartner arrived at the Gruber family farm in wooded, rural Bavaria to start her new job as the Gruber family's maid. The position had been vacant for over six months, so the farmhouse was undoubtedly in need of a good cleaning. But little did Maria know that within hours of setting to work scrubbing months' worth of grime off of the family's floors and windows, she would also become a victim of one of Germany's most brutal unsolved mass murders.