They had met the 19-year-old at a job training camp for disadvantaged young people.
According to court documents, Pike feared Ms Slemmer had a romantic interest in Shipp.
Pike was then diagnosed with bipolar and post-traumatic stress disorders, her attorneys said.
Because Shipp was legally a minor at the time of the murder, he was not handed the death penalty and now remains in prison.
May Martinez, Ms Slemmer’s mother, said she broke down in tears when she learned of Pike’s survival.
“She was lying on the table, talking, still laughing, picking up her head”, she told ABC.
Ms Martinez said the state owed her a “big apology”, adding: “All I wanted was justice.”
