Hillary Clinton’s FBI investigation may have just moved one step closer to an indictment for the Democratic front-runner, with experts saying the extradition of a Romanian hacker who revealed her unsecured email server could spell deep trouble for Clinton’s presidential campaign.

Last week, U.S. officials moved to extradite the hacker known as “Guccifer,’ who is accused of accessing the email of Clinton adviser Sidney Blumenthal. It was that hack which brought to light Clinton’s use of a personal email during her time as secretary of state, reports claim.

The hacker, whose real name is Marcel Lehel Lazar, will now be able to make the case that Hillary Clinton’s email server was unsecure and could have spilled secrets to America’s enemies, Fox News experts Catherine Herridge and Pamela K. Browne wrote.

“Because of the proximity to Sidney Blumenthal and the activity involving Hillary’s emails, [the timing] seems to be something beyond curious,” the report quoted Ron Hosko, former assistant director of the FBI’s Criminal Investigative Division.

Lazar was brought to the United States near the end of March and appeared at a Virginia federal court this week to face hacking charges, the report noted.

The report added that the timing of his extradition is curious given the ongoing investigations of Clinton’s alleged use of a private, unsecured email during her time as secretary of state, and noted that Guccifer’s testimony could be a major blow to Clinton.

In early 2013, news outlets including Russia Today and The Smoking Gun published memos from Guccifer, with excerpts of exchanges between Blumenthal and Hillary Clinton about Libya including details following the 2012 Benghazi terrorist attack. “In a 2015 prison interview from Romania with reporter Matei Rosca for Pando.com, Lazar told Rosca that, “I used to read [Clinton’s] memos for six or seven hours… and then do the gardening.”

For her part, Hillary Clinton has waved off concerns of a potential FBI indictment for her email server. In an interview with NBC’s Matt Lauer that aired on Friday, Clinton dismissed claims that she is under investigation, instead calling the FBI probe a “security review.”

Hillary Clinton says the FBI hasn’t contacted her yet about her use of a private email server https://t.co/gHQoh3Kjwx via @WSJPolitics — Wall Street Journal (@WSJ) April 4, 2016

“Oh my goodness,” Clinton said (via Politico). “Well, Matt, I know that they live in that world of fantasy and hope because they’ve got a mess on their hands on the Republican side. That is not gonna happen. There is not even the remotest chance that it’s going to happen.”

Both Republican opponents and backers of Bernie Sanders have used the possibility of an indictment as a knock against Clinton. Clinton insisted that her campaign would continue on, noting that the talk of a possible indictment is more of the same conservative smears she has faced dating back to her time as First Lady.

“The Republicans’ fondest wishes will not be fulfilled,” she said.

There's no reason to rush probe into Hillary Clinton's email server, says @FBI Director. https://t.co/4xQP3gzHqN. pic.twitter.com/Sk4LClTk42 — CNN Breaking News (@cnnbrk) April 5, 2016

Whatever comes of Hillary Clinton’s FBI investigation, there may not be a conclusion anytime soon. This week, FBI director James Comey said there is no need for undue urgency in the probe of Clinton’s email server, though Comey did say he was planning to stay “close to this one to make sure we have the resources to do it competently.”

Sources had previously told CNN that the FBI investigation into Hillary Clinton’s email server was reaching its “final phases,” though it was not clear just how long that was expected to take.

[Picture by Alex Wong/Getty Images]