Free speech
© Reuters / Simon Dawson
Julian Assange could be charged under the Espionage Act for leaking classified material in addition to the hacking charge he already faces, a US Department of Justice document indicates.

The Department of Justice (DOJ) is investigating "possible violations of United States federal criminal law regarding the unauthorized receipt and dissemination of classified information," said a letter addressed to former WikiLeaks spokesman Daniel Domscheit-Berg, requesting an interview.

The letter suggests the DOJ is looking for evidence to charge the WikiLeaks founder with more than the computer crime detailed in the indictment against him unsealed in April.

The Espionage Act, a 1917 law intended to protect military secrets, has been used as a powerful implement against whistleblowers. Chelsea Manning was sentenced to 35 years in prison under the Act for her role in leaking evidence of US war crimes in Iraq and Afghanistan, while Edward Snowden was hit with two charges under the Act for his disclosures related to mass surveillance.

Investigations into WikiLeaks started as early as 2008, even before the publication of the Iraq and Afghan war logs, as well as the horrific 'Collateral Murder' footage. The DOJ began its own probe into Assange one year later, after WikiLeaks published nearly five decades' worth of State Department diplomatic cables.

Assange is currently in British custody awaiting an extradition hearing after his April arrest at the Ecuadorian Embassy in London. British law mandates that suspects cannot be extradited to countries with the death penalty; it is unclear whether the DOJ's probe will affect that process.