House later added that he did not receive a subpoena himself. The identity of the recipient is not yet publicly known.
From the Wikileaks Twitter account that same day: "Fresh subpoenas are being issued in the WikiLeaks Alexandra, VA secret grand jury in relation to the espionage act."
Glenn Greenwald at Salon writes that the FBI served at least one subpoena in Boston, and that this was presumably related to the Wikileaks case.
Notably, the Subpoena explicitly indicates that the Grand Jury is investigating possible violations of the Espionage Act (18 U.S.C. 793), a draconian 1917 law under which no non-government-employee has ever been convicted for disclosing classified information.
And Wikileaks, being Wikileaks, tweeted out the D.A.'s phone number.