(1929-1990) One of the most disturbing murderers in Indiana history (and indeed history in general), a demon disguised as a mother. A three times divorced borderline personality and sociopath who lead her seven children and several neighborhood children in the appalling two-month torture in 1965 of two sisters who she was boarding, Silvia and Jenny Likens (ages 16 and 15) and eventually murdered Silvia.
The stronger of the pair, Silvia took the brunt of Gertrude's fury; she called Silvia filthy (Gertrude's own house was a virmin-ridden hellhole), called her a whore (Gertrude had fucked another man during one of her three marriages (resulting in a child) and her own teenage daughter was a slut who was pregnant by a married man) and subjected the girls (and Silvia in particular) to physical, verbal, and sexual tortures that are nightmares to even conceive of.
Neighbors had noticed the battered state of the Likens girls, but they did not report Gertrude.
Gertrude tried to pin the crimes on her children and the neighborhood children when Silvia's hideously mangled body was found.
In other words, a demon

Anger or rage ignited by a perceived or real injustice/ offense; resentment or bitterness. The resulting feeling when one feels that they have been snubbed or screwed over, pissed off.