PASADENA – Police have arrested a man they suspect of up to 30 Southern California murders, which has prompted Pasadena Police detectives to crack open unsolved homicide files that could potentially be connected.

John Floyd Thomas Jr. was arrested earlier this month in connection with two Los Angeles killings after Los Angeles police detectives connected him to DNA found at the scenes. Police announced Thursday he is also being investigated as a suspect in at least 25 other cases, all of which targeted older women.

Thomas was also arrested in Pasadena in 1978 on suspicion of rape, but was convicted of lesser charges, said Pasadena Police Department Spokeswoman Janet Pope Givens.

Now detectives are looking into whether any unsolved cases may fit the same description, she said.

“The cold case unit is taking a look at it in terms of some of the other unsolved homicides that may have taken place prior to and after, to see if there is any relation,” Givens said.

Specifically, they are looking at cases of women who were killed late 1970s and early 1980s. Givens did not cite any specific cases.

Thomas’ arrest record, which is more than 30 years old, is no longer available, she said.

Thomas, who once lived in Chino, has been charged with two killings so far, and DNA matching his was found at a total of three other crime scenes in West Los Angeles in the 1970s and Claremont in the 1980s, Los Angeles police robbery-homicide Capt. Denis Cremins said.

Los Angeles detectives continue to look through unsolved cases dating back to the mid-1950s, he said.

In addition to dozens of killings, police suspect Thomas may have committed scores of unsolved sexual assaults possibly dating back as far as the mid-1950s, said Deputy Chief Charlie Beck of the Los Angeles Police Department.

“We have not yet reached the depth” of what Thomas is capable of, Beck said at a press conference Thursday afternoon.

One of the cases Los Angeles County sheriff’s investigators have linked to Thomas using DNA evidence is the June 1986 strangling death of Adrienne Askew, said Claremont police Capt. Gary Jenkins.

Askew, 56, was attacked in her apartment in the 600 block of West Bonita Avenue, according to news reports of the incident.

Aspects of Askew’s death, as described in 1986 news reports, appear consistent with police descriptions of Thomas’ alleged killing methods.

Detectives are also investigating Thomas as a possible suspect in at least one other attack in Claremont from the 1980s, police said.

Thomas remained jailed Thursday without the possibility of bail, and is next due in Los Angeles Superior Court on May 20 for an arraignment hearing.

In the first wave of killings in Los Angeles in the mid-1970s, a man police dubbed “The Westside Rapist” entered the homes of elderly women who lived alone, raped them and choked them until they passed out or died, according to news reports.

The 17 people killed were found with pillows or blankets over their faces.

During that time, Thomas was a social worker, hospital employee and salesman.

The attacks stopped in 1978 – the year he went back to prison for the rape of a Pasadena woman.

After his 1983 release, he moved to Chino and took a job as a hospital peer counselor in Pomona. That year, a series of attacks on elderly women began that included at least one slaying in Claremont.

Investigators say the wave of attacks stopped in 1989 – the year Thomas began working in Glendale.

At Thomas’ May 20 arraignment hearing, the district attorney’s office will announce possible charges for the additional killings linked to Thomas by DNA, according to a Los Angeles Police Department news release.

If convicted of the two counts of murder, Thomas could face life in prison without the possibility of parole. Prosecutors may seek the death penalty if Thomas is convicted of any killings after 1978, Beck said.

Thomas’ defense attorney, Deputy Public Defender Raoul Hutchens, did not immediately return a call seeking comment Thursday afternoon.

The prosecutor handling his case, Deputy District Attorney Darci A. Lanphere, was not available for comment Thursday, a district attorney’s office spokeswoman said.

The victims in all 30 cases under review were older white women, mostly of lower incomes and often widows living alone, said Cremins. All had been sexually assaulted and most were strangled.

– Staff writers Robert S. Hong, Will Bigham, Joe Blackstock and Lori Consalvo contributed to this report