Detectives from the Los Angeles Police Department hold a news briefing
Los Angeles police believe a 72-year-old man now in custody could be the city's most prolific serial killer.
Detectives suspect John Floyd Thomas Jr may be responsible for a spate of rapes and murders in the 1970s and 1980s.
He has been linked by DNA evidence to five murders, two of which he has been charged with, and is now a suspect in as many as 25 more, officials said.
Police believe he may be the notorious Westside Rapist, who terrorised Los Angeles suburbs in the 1970s.
Thomas spent time in prison between 1957 and 1983 for sexual crimes, and it was because of those convictions that his DNA was taken in 2008 as part of a process to collect samples from sex offenders.
He was arrested on 31 March and charged a few days later with the murder of a 68-year-old woman in 1972 and a 67-year-old woman in 1976, both of whom were sexually assaulted and strangled.
Police Capt Denis Cremins said on Thursday that DNA matching Thomas's was found at three other crime scenes in the 1970s and 1980s.
John Floyd Thomas Jr is a former insurance claims adjuster
Capt Cremins said that Thomas, a former state insurance claims adjuster, is now a suspect in at least 25 other killings, and the number could grow as detectives re-investigate unsolved cases going back to the 1950s.
"If he turns out to be the guy, he probably would be the largest ever (serial killer) in the city of Los Angeles," he said.
In the first wave of killings in the mid-1970s, a man dubbed the Westside Rapist entered the Los Angeles homes of dozens of elderly women, raped them and choked them. Seventeen of the victims died.
During that time, Thomas worked as a social worker, a hospital employee and a salesman.
Police say the attacks stopped in 1978 - the year Thomas went back to prison for the rape of a woman in Pasadena.
He was released in 1983, the year that another series of attacks on elderly women began, detectives say.
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