Kerry Lynn Dalton -- California

In 1988, Dalton murdered a woman in Live Oak Springs, Calif., because she 
thought the woman had stolen her jewelry. Dalton confessed to torturing 
the woman with electrical wires, a cast-iron skillet and injections of 
battery acid. The victim’s body was never found. 

http://abcnews.go.com/sections/us/deathrow/deathrow_women.html

Dalton's own home page (she claims she never confessed):
http://ccadp.org/kerrydalton.htm