Hacker 'Guccifer': I Got Inside Hillary Clinton's Server

The Romanian hacker who first exposed Hillary Clinton's private email address is making a bombshell new claim—that he also gained access to the former Secretary of State's "completely unsecured" server.

"It was like an open orchid on the Internet," Marcel Lehel Lazar, who uses the devilish handle Guccifer, told NBC News in an exclusive interview from a prison in Bucharest. "There were hundreds of folders."

Lazar was extradited last month from Romania to the United States to face charges he hacked political elites, including Gen. Colin Powell, a member of the Bush family, and former Clinton advisor Sidney Blumenthal.

A source with knowledge of the probe into Clinton's email setup told NBC News that with Guccifer in U.S. custody, investigators fully intend to question him about her server.

When pressed by NBC News, Lazar, 44, could provide no documentation to back up his claims, nor did he ever release anything on-line supporting his allegations, as he had frequently done with past hacks. The FBI's review of the Clinton server logs showed no sign of hacking, according to a source familiar with the case.

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Hillary Clinton has always maintained that the server was not breached. On Tuesday she told Andrea Mitchell on MSNBC that she had no indication that her server was hacked by foreign hackers.