washington romanian computer hacker reveal existence private email server use hillary clinton secretary state plead guilty hacking-related offenses wednesday u.s. justice department say marcel lazar use alias guccifer enter guilty plea judge jam cacheris u.s. district court alexandria virginia department say statement sentence set sept. 1. recent media interview lazar claim easily hack clinton controversial private email server justice department statement confirm claim law enforcement official say investigators find evidence support claim hacker expose hillary clinton 's email server plead guilty