Grete Beier

Grete Beier, the eighteen-year-old daughter of the Mayor of Freiburg, 
was beheaded in private in the town prison at Freiburg, Saxony, 
before dawn on July 22nd 1908 for the murder of her fiancée, a civil 
engineer named Proffler, whom she had poisoned for financial gain.

http://www.geocities.com/CapitolHill/6142/behead.html