Prosecutors have obtained a sealed indictment against Assange, something that emerged in a Thursday filing in an unrelated criminal case in a Virginia federal court.
Prokupecz noted, however, the revelation of the indictment "could hurt" the US government's chances in ever having Assange face the charges.
Assange's charges were unintentionally revealed in the August 22 court filing, which centered on a sex trafficking case with a perpetrator who was also detained for "his substantial interest in terrorist acts".
Assange refuses to leave the embassy, where Ecuador has granted him asylum, because he believes the United States will seek to have him extradited over WikiLeaks activity - something that, for the first time, there is now evidence the Justice Department may seek to do.
In one sentence, the prosecutor wrote that the charges and arrest warrant "would need to remain sealed until Assange is arrested in connection with the charges in the criminal complaint and can therefore no longer evade or avoid arrest and extradition in this matter".
In a separate statement to the Post, Pollack said, "The only thing more irresponsible than charging a person for publishing truthful information would be to put in a public filing information that clearly was not intended for the public and without any notice to Mr. Assange".More news: John Kelly Might Leave WH After Clash With Melania
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The Washington Post reported Thursday night that Assange has, in fact, been charged, citing the inadvertent court disclosure as well as people familiar with the matter, but precisely what criminal charges he faces remains unclear.
According to the document, defendant Kokayi is accused of the coercion and enticement of a minor.
Julian Assange speaks to the media from the balcony of the Ecuadorian embassy in London on May 19, 2017. It looks as if the prosecutor copied text from a similar case and neglected to swap out Assange's name. New Yorker magazine, however, reported an anonymous source as saying that Assange named it Michi, "which is Ecuadorean Spanish for cat", having spent half an hour staring at it and trying to work out a PR strategy that made the cat reflect well on him.
With shrinking options - an Ecuadorian lawsuit seeking to reverse the restrictions was recently turned down - WikiLeaks announced in September that former spokesman Kristinn Hrafnsson, an Icelandic journalist who has long served as one of Assange's lieutenants, would take over as editor-in-chief. Lawyers for Assange didn't respond to requests for comment.
Assange has been under investigation ever since WikiLeaks published thousands of classified government documents, including diplomatic cables and military documents, starting in 2010. Bradley (now Chelsea) Manning.
Wikileaks said in a Twitter post it was an "apparent cut-and-paste error".