Possible offenses under consideration include conspiracy or trafficking in stolen property, The New York Times reported Wednesday.
Attorney General Eric H. Holder Jr. said this week prosecution was problematic under the Espionage Act, a World War I-era law under which makes unauthorized possession and dissemination of national defense-related information illegal. However, Holder signaled his office was looking at other statutes.
"I don't want to get into specifics here, but people would have a misimpression if the only statute you think that we are looking at is the Espionage Act," Holder said Monday. "That is certainly something that might play a role, but there are other statutes, other tools that we have at our disposal."
Last week, five news organizations, including the Times, began publishing articles based on more than 250,000 U.S. State Department documents obtained and released by WikiLeaks. After releasing government documents concerning the wars in Iraq and Afghanistan, Holder and FBI Director Robert Mueller both said the leaks were being investigated.
Assange was arrested Tuesday in London on a Swedish arrest warrant concerning accusations of sexual assault.
Sen. Joseph Lieberman, Ind-Conn., told Fox News Tuesday he believed the Times should be investigated in addition to WikiLeaks, cautioning that this was a sensitive discussion because "it gets into the America's First Amendment."
"I certainly believe that WikiLeaks has violated the Espionage Act, but then what about the news organizations -- including the Times -- that accepted it and distributed it?" Lieberman said. "To me, The New York Times has committed at least an act of bad citizenship, and whether they have committed a crime, I think that bears a very intensive inquiry by the Justice Department."