Hacker group Anonymous said it had disabled the US Sentencing Commission's website in revenge for the death of internet freedom advocate Aaron Swartz, and vowed to release government data.
The website of the commission, an independent agency of the US Justice Department involved in sentencing, was apparently hacked into early Saturday.
Anonymous threatened to make public the encryption keys to files that could potentially embarrass judges and other federal employees, saying it acted in protest at the Justice Department's alleged mishandling of Swartz's case.
Swartz was facing 35 years in prison and a $US1 million ($A960,661) fine for breaking into a closet at the Massachusetts Institute of Technology to plug into the computer network.
He downloaded millions of academic journal articles he had allegedly planned to distribute for free.