Mary Virginia Jones was convicted of first-degree murder, kidnapping and robbery and sentenced to life without parole for a killing committed alongside boyfriend Mose Willis, who died while on death row.
She always maintained that the abusive Willis forced her at gunpoint to help him rob and shoot two drug dealers, one of whom died.
Law students at the University of Southern California's Post-Conviction Justice Project took up her cause. Los Angeles County prosecutors conducted a new investigation and agreed to accept a plea of no contest for involuntary manslaughter.
Judge William C Ryan ruled yesterday afternoon that Jones had served well over the 11-year maximum sentence for the lesser crime and ordered her freed.
She walked out of prison yesterday and was met by joyful family and friends, the Los Angeles Times reported.