Los Angeles - Police in Los Angeles identified a 72-year-old insurance adjuster Thursday as the city's worst serial killer, charging him with two murders in 1972 and 1976 and linking him with 25 others.

Police said that DNA matching John Floyd Thomas Jr was found at three other murder scenes from the 1970s and 1980s and that detectives were examining his connection to other cases linked to the notorious Westside Rapist.

The killings and rapes took place in west Los Angeles in two waves, between 1972-78 and 1983-89. During the five-year gap, Thomas was serving a prison sentence after being convicted of rape. In 1989, Thomas took a job with a state insurance agency.

Most of the victims were elderly white women, many in their 70s and 80s, who were raped and strangled.

"When all is said and done, Mr Thomas stands to be Los Angeles' most prolific serial killer," Richard Bengston of the Los Angeles Police Department told the Los Angeles Times.

Thomas was arrested on April 2 at his Los Angeles home. Twice previously convicted of sexual assault, he was linked to the long- cold cases when his DNA was taken as as part of an ongoing process to take swab samples from registered sex offenders.