[GHFigs]

Obama's DOJ has convened a secret grand jury investigating Assange under the Espionage Act.

All grand jury proceedings are secret. This is a normal part of the US legal system.

http://en.wikipedia.org/wiki/Grand_juries_in_the_United_Stat...

[brl]

but not all of the subpoenas are secret, certainly is it rare for them to include NSLs (as Appelbaum has indicated the FBI hinted) and rarely if never are the dockets themselves sealed (as Appelbaum's lawyer is currently fighting)