The infamous Romanian hacker Guccifer who exposed the existence of Hillary Clinton's private email domain used while she was US secretary of state has been sentenced to 52 months in prison by a federal court in Alexandria, Virginia. The 44-year-old former taxi driver, whose real name is Marcel Lehel Lazar, pleaded guilty in May to charges including aggravated identity theft and unauthorised access to a protected computer after being extradited to the US from Romania.

Lazar has admitted to hacking email and social media accounts of about 100 victims between 2012 and 2014 from his home overseas. The cybercriminal rose to notoriety after hacking into the email accounts of multiple high-profile political figures including former secretary of state Colin Powell and former Clinton White House aide Sidney Blumenthal.

The breach into email accounts associated with the Bush family resulted in leaked emails, telephone numbers, home addresses, medical information and personal photographs, including one of former president George H W Bush in the hospital and nude self-portraits of former president George W Bush.

Lazar was also the first person to expose Clinton's private email address that she used during her time as secretary of state to conduct both personal and official business instead of her government account, by leaking online memos Blumenthal sent to the private account. The revelation eventually led to an FBI investigation and continuous scrutiny from Republicans, including GOP presidential nominee Donald Trump, over the matter in the run-up to the upcoming November presidential election.

Marcel Lazar Lehel is escorted by masked policemen in Bucharest, after being arrested in Arad, 550 km (337 miles) west of Bucharest , on 22 January, 2014 Reuters/Mediafax/Silviu Matei

Lazar also claimed to have breached Clinton's "completely unsecured" private server recently, a claim that authorities dismissed as lacking in evidence.

"This epidemic must stop," US District Judge James C Cacheris reportedly said as he handed out the 52-month sentence, adding that a tough penalty was necessary to deter future hackers.

He mentioned reports of rising cyberattacks against Americans in the past few years, including the FBI's recent warnings to state officials to bolster their election security in light of evidence that hackers have already successfully penetrated election databases in two states.

In seeking a maximum sentence of four and a half years under US sentencing guidelines, assistant US attorney Maya D Song wrote that a harsher punishment "would also help address any false perception that unauthorised access of a computer is ever justified or rationalized as the cost of living in a wired society — or even worse, a crime to be celebrated".

Federal prosecutors also referred to the new entity called Guccifer 2.0 that claimed credit for the recent much-publicised, massive breaches at the Democratic National Committee and Democratic Congressional Campaign Committee. While US intelligence officials and cybersecurity experts see a Russian intelligence services link, the Kremlin has vehemently denied any involvement in the breaches.

Lazar will be sent back to Romania to serve a sentence in his home country before returning to the US in 2018 to serve out his stateside prison term, Cacheris said.