Prosecutors on Wednesday added five new murder charges to the two already filed against Thomas. They involve victims ranging in age from 56 to 80 years old.
In April, Thomas was charged with the 1972 murder of 68-year-old Ethel Sokoloff in her mid-Wilshire home, and the 1976 killing of 67-year-old Elizabeth McKeown in Westchester.
Los Angeles police investigators reported that DNA evidence linked him to the killings. They said they were looking into his possible connection to as many as two dozen other murders and rapes between 1955 and 1978.
The new charges involve three women who lived in Inglewood, one who lived in the Lennox area, and one who lived in Claremont. They were killed between September 1975 and June 1986.
The charges include special circumstances that could make Thomas eligible for the death penalty. Prosecutors have not decided if they will pursue a death penalty conviction.
Thomas is being held in jail without bail. He's due back in court November 12, when a date will be set for his preliminary hearing.
City News Service contributed to this story.