Transcript for Hillary Clinton Hands Over Private Server

Hillary Clinton enjoying some of the famous fried food here at the Iowa state fair yesterday. But she couldn't escape a grilling from reporters about her private e-mail server and that FBI investigation. The democratic front-runner is pushing back hard, arguing the controversy is just partisan politics. ABC's Jon Karl has the latest. Reporter: Out in Iowa this weekend, Hillary Clinton joked about the thousands of e-mails she deleted from her time as secretary of state. I recently launched a snapchat account. I love it. I love it. Those messages disappear all by themselves. Reporter: But her infamous private server is now in the hands of the FBI, which is intensifying its investigation into the handling of classified information in her e-mails. According to sources familiar with the investigation, it's already been determined that at least two of the e-mails included information that's top secret, some of it from so-called signals intelligence, among the most sensitive intelligence there is. Investigators are also trying to determine if the Chinese or Russians were able to get access to Clinton's private e-mails. Anyone who works around this level of classified information knows the sensitivity. Reporter: In the most intriguing new development, Platte river networks, the Colorado company that set up her server, told ABC news it's highly likely that a full backup of the server was made. Those thousands of e-mails she deleted may still exist. The company says it's cooperating with the FBI. Clinton continues to brush off questions about her e-mails as a partisan distraction. I think that, you know, this is the usual partisanization of anything that goes on. And I have been at this for a really long time. Reporter: Republicans say it's much more than that. She should come clean and deal with this. This is an issue. It's not a distraction, for sure. Reporter: Hillary Clinton's troubles may be creating an opening for a democratic challenger. Bernie sanders is already surging and Joe Biden spent last week weighing his options. Hillary Clinton is now here on Martha's vineyard where she saw president Obama at a birthday party for a mutual friend. White house officials are watching weary as vice president Biden makes his decision. As one top official told me, it would be awkward if Biden decides to run and the president has to remain neutral in a race that pits his former secretary of state against his vice president.

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