The Romanian hacker whose exploits revealed former Democratic presidential nominee Hillary Clinton's use of a private email server while she was Secretary of State has been sentenced to 52 months in prison, the Justice Department said Thursday.

After extradition from Romania, Marcel Lazar, aka Guccifer, had pleaded guilty in federal court in the Eastern District of Virginia to a number of charges last May.

While authorities have remained skeptical of his claims that he breached Clinton's server, noting that there is no evidence to back up the assertions, the 44-year-old Romanian is believed to have hacked former Secretary of State Colin Powell, former Clinton White House Aide Sidney Blumenthal and scores of others over a two-year span beginning in 2012.