We had a guy around here (Rochester, New York) named Arthur Shawcross. He murdered 2 children in Watertown (WAY up North). Was sentenced to - I'm not sure, I think it was 20 years. He served about 13 years and was released on parole.
He murdered 11 women before they put him away again. 11 consecutive terms of 25-to life. New York didn't have a death penalty at the time.
They had another guy in Texas named Ken McDuff, sentenced to death in 1969 (I think). When the Supreme Court endced the death penalty a few years later, McDuff's sentence was commuted to life. He got parole and murdered 7 women. He has since been executed.
McDuff will never commit murder again. I'm not as sure about Shawcross.