The hacker who goes by the name "Guccifer 2.0" on Friday released files purportedly stolen in a cyberattack on the Democratic Congressional Campaign Committee.
The documents posted online do not appear to contain any email or communications, but rather include shared passwords for the committee's shared accounts to various news services, Lexis, and a federal courts public access system called PACER.
Documents purportedly showing Congressional contact lists and campaign overviews were also released.
A committee spokesperson said they are cooperating with federal authorities investigating the cyberattack. "We are aware of reports that documents claimed to be from our network have been released and are investigating their authenticity," DCCC national press secretary Meredith Kelly said in a statement.
The intrusion in the Congressional committee's computer system was disclosed in late July. At the time, officials said it appears similar to a hack on the Democratic National Committee.
The Democratic National Convention was thrown into some early controversy when internal emails between DNC officials were posted by the website WikiLeaks days before the convention began. Those emails appeared to show a bias among some officials in favor of Hillary Clinton, which angered some Bernie Sanders supporters.
The cyberattacks have raised concerns among U.S. national security officials that outside groups or governments could be trying to interfere in the presidential election.