The FBI said Friday that it pulled fingerprints off decades-old immigration papers to identify the kidnapping suspect who calls himself Clark Rockefeller as a German man who came to the U.S. as a youth and later adopted several aliases.

The FBI said it obtained fingerprints from immigration documents of Christian Gerhartsreiter that dated from the early 1980s, when Gerhartsreiter came to country legally.

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The FBI said those fingerprints matched those taken from a wine glass Gerhartsreiter touched around the time he allegedly kidnapped his daughter off a Boston street in late July, as well and fingerprints taken by Baltimore police near the time of his Aug. 2 arrest.

Authorities have said Gerhartsreiter lived all around the U.S., including California, Wisconsin and Massachusetts, under aliases including Chris Crowe, Chris Chichester, Charles Smith and Chip Smith

"Gerhartsreiter is at the center of the longest con I've ever seen in my professional career," said Suffolk County District Attorney Daniel Conley.

Authorities in California are seeking to question Gerhartsreiter about the disappearance of a San Marino couple who owned a guest house where he lived. The Los Angeles County Sheriff's Department has labeled Gerhartsreiter a "person of interest" in the case, but he has refused to talk to their investigators. No charges have ever been filed in the missing persons case.

Earlier this week, the sheriff's department identified Rockefeller as Gerhartsreiter, relying on numerous interviews with people who knew him in California in the 1980s. Conley said that wasn't enough to prosecute the case.

"As prosecutors, we need more than a photo and a fading memory to walk into court and amend a complaint," he said.

Conley said that by matching recent fingerprints to those on the old papers, "the FBI's fingerprint technicians brought science to bear where mere suspicion had prevailed."

Rockefeller attorney, Stephen Hrones, has said Rockefeller does not remember his childhood in Germany or his time in California during the 1980s.

Hrones did not immediately return a call for comment Friday.

Police have said he snatched his daughter from a Boston street during a supervised visit on July 27 after hiring two people to drive them to New York.

At the time of his arrest in Baltimore, Gerhartsreiter had allegedly been living as Clark Rockefeller and making plans to start a new life with his daughter.

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