Anonymous have dumped 1.7GB of data belonging to the US Department of Justice, and on the flip side, the DoJ have downplayed the sensitivity of the data siphoned from their website. Anonymous says that the information they have includes "internal e-mails", and "the entire database dump" from the website.
Anonymous' leak was announced alongside a torrent with the 1.7GB of data inside, as well as a statement:
Today we are releaseing [sic] 1.7GB of data that used to belong to the United States Bureau of Justice, until now. Within the booty you may find lots of shiny things such as internal emails, and the entire database dump. We Lulzed as they took the website down after being owned, clearly showing they were scared of what inevitably happened.
The reason for the attack is unknown, but Anonymous say that it's releasing the data to "spread information, to allow the people to be heard and to know the corruption in their government". The flip side has a DoJ spokesperson fanning out the flames, where they've said to ZDNet that a website with public information had been accessed, and that they were looking into the matter in more depth:
The department is looking into the unauthorized access of a website server operated by the Bureau of Justice Statistics that contained data from their public website. The Bureau of Justice Statistics website has remained operational throughout this time. The department's main website, justice.gov, was not affected.