Prosecutorial Box

Charges against the executive branch are investigated by the Attorney General:

28 USC §591
Release date: 2004-10-27
  (a) Preliminary Investigation With Respect to Certain Covered Persons.– The Attorney General shall conduct a preliminary investigation in accordance with section 592 whenever the Attorney General receives information sufficient to constitute grounds to investigate whether any person described in subsection (b) may have violated any Federal criminal law other than a violation classified as a Class B or C misdemeanor or an infraction.
  (b) Persons to Whom Subsection (a) Applies.–The persons referred to in subsection (a) are–
    (1) the President and Vice President;

Followed by just about everyone else in the Executive Branch.

::A Bit More::

Since the Attorney General was serving as an advisor to the President during the time the infractions occurred, I suggest he would have to recuse himself:

(e) Recusal of Attorney General.–
(1) When recusal is required.–
  (A) If information received under this chapter involves the Attorney General, the next most senior official in the Department of Justice who is not also recused shall perform the duties assigned under this chapter to the Attorney General.

Deputy Director James B. Comey has resigned, replaced by one Timothy Elliot Flanigan:

…… Flanigan leaves his current post as senior vice president and general counsel for Tyco International. He has close ties to the Administration, formerly serving as Attorney General Gonzales’ deputy in the White House counsel’s office from 2001-2002 and contributing to the litigation team for the Bush-Cheney campaign in the 2000 Presidential election.  Comey will remain at D.O.J. until the end of the summer. [WatchingJustice]

Those who think they have enough evidence to investigate the President, or any other member of the Executive Branch should be asking who’s third in line.