Chester Turner has already been convicted for 10 killings between 1987 and 1998, as well as the death of an unborn fetus.
New charges allege that Turner killed four other women between 1987 and 1992.
The murder charges include the special-circumstance allegations of multiple murders and murder during the commission of a rape or attempted rape of all four victims, which makes Turner eligible for the death penalty.
Prosecutors have not yet decided whether to pursue the death penalty again.
He is scheduled to be arraigned on those charges Nov. 22.
The Associated Press contributed to this report.