They are also asked as can be read on politico.com, that they are asked to stop using e-mail as well. It is stated there as well that 7 GB of information is gone for good.
The Washington Post quotes that there is no proof, but when you can read between the lines, it is clear that they believe they have been hacked.
One News from New Zealand says "In another case, system administrators were searching files at prosecutors' request and were able to access more than 500,000 defense files, including confidential attorney-client communications, [...]". There were also bugs placed.
Due to all this, hearings are postponed as can be read on reuters"