A spokeswoman for the UC Davis Medical Center in Sacramento says Nesler died there Friday morning. The 56-year-old had battled breast cancer since 1994.
Nesler shot Daniel Driver five times in the head during a break in his preliminary hearing in a Tuolumne (too-WAH'-lum-ee) County courtroom. Driver had been accused of molesting four boys, including her son Willy.
She was convicted of voluntary manslaughter and served three years of a 10-year sentence before winning an appeal based on jury misconduct.
The case became a 1999 TV movie, "Judgment Day: The Ellie Nesler Story."