The FBI has not ruled out the possibility that Hillary Clinton's email was hacked

FBI Director James Comey said Tuesday that investigators did not find "direct evidence" that Hillary Clinton's private email server had been hacked, but did not rule out that possibility.

In a statement to the press following its investigation into Clinton's use of a private email server while serving as Secretary of State, Comey said a variety of factors led the FBI to assess that "it is possible that hostile actors gained access to Secretary Clinton's personal e-mail account."

In May, the infamous Romanian hacker "Guccifer" said he had hacked into the private server, but offered few details on how he pulled it off. Though his claims could not be verified, the hacker did successfully breach other close confidantes of Clinton's, and was the first to expose the existence of the server.

For his part, Comey said that the FBI did not find "direct evidence" the server was successfully hacked, but he added, "given the nature of the system and of the actors potentially involved, we assess that we would be unlikely to see such direct evidence."

Translation: We did not find the fingerprints of hackers on this system, but hackers often cover up their tracks and delete traces of their breaches, so it's very possible they broke in and we would never know it.

Of whether the server was hacked, Clinton's website says: "No, there is no evidence there was ever a breach."

Comey also talked about "hostile actors" who did gain access to private email accounts of people Clinton emailed. Though he didn't name names, at least one of those actors was Guccifer, whose real name is Marcel Lehel Lazar.

"She also used her personal e-mail extensively while outside the United States, including sending and receiving work-related e-mails in the territory of sophisticated adversaries," Comey said. "Given that combination of factors, we assess it is possible that hostile actors gained access to Secretary Clinton's personal e-mail account."