Not every villain in the "Harry Potter" franchise is an evil Death Eater — or ... Take Dolores Umbridge (Imelda Staunton), for example, who first shows up in "Harry Potter and the Order of ...
Dumbledore and Umbridge used Veritaserum during interrogations ... It was always difficult to tell whether a witch or wizard was a Death Eater, but Veritaserum could have thinned the herd.