Homicide detectives "are confident that Rockefeller is Christian Gerhartsreiter and the person named Christopher Chichester who was living in the Los Angeles area in 1985," Whitmore said.
Gerhartsreiter has been identified as a "person of interest" in the San Marino case, Whitmore said.
Investigators were able to confirm Gerhartsreiter's identity after interviews with people who knew him in California in the 1980s, Whitmore said.
Under the Chichester name, Gerhartsreiter rented a guesthouse at the home of Jonathan and Linda Sohus, who vanished in 1985 while living in wealthy San Marino, about 10 miles northeast of Los Angeles.
At the time of his Aug. 2 arrest in Baltimore, Gerhartsreiter had been living under the Rockefeller name. Police have said he snatched his daughter from a Boston street on July 27 in an elaborately planned kidnapping in which he hired two people to drive them to New York.
In the San Marino case, skeletal remains were unearthed at the Sohus property in 1994 when new owners were putting in a swimming pool. Investigators at the time were unable to identify the bones but believed they probably belonged to Jonathan Sohus. Investigators have requested a new round of forensic tests, Whitmore said.
Los Angeles County sheriff's investigators tried to question Gerhartsreiter in Boston last week, but he declined. No charges have ever been filed in the missing-people case.
Stephen Hrones, his attorney in the Boston kidnapping case, said Rockefeller does not remember his childhood in Germany or his time in California during the 1980s.
When told that Los Angeles County investigators had identified Rockefeller as Gerhartsreiter and Chichester, Hrones said, "They can do what they want with it, but he doesn't remember anything. He remembers nothing before 1993, except for little bits and pieces."
Slideshow archive | ABC13 wireless | Help solve crimes