If you were to throw a pebble into the well that is the IRS scandal, you would still be waiting to hear the stone hit water. The scandal has yet to bottom out and every revelation gives the lie to the original narrative that a couple of "rogue" IRS employees at the Cincinnati office are solely responsible.

NBC is reporting that letters obtained by counsel for groups who were targeted show senior management at the IRS intimately involved in requesting information on conservative groups:

Additional scrutiny of conservative organizations' activities by the IRS did not solely originate in the agency's Cincinnati office, with requests for information coming from other offices and often bearing the signatures of higher-ups at the agency, according to attorneys representing some of the targeted groups. At least one letter requesting information about one of the groups bears the signature of Lois Lerner, the suspended director of the IRS Exempt Organizations department in Washington.

Jay Sekulow, an attorney representing 27 conservative political advocacy organizations that applied to the Internal Revenue Service for tax-exempt status, provided some of the letters to NBC News.  He said the groups' contacts with the IRS prove that the practices went beyond a few "front line" employees in the Cincinnati office, as the IRS has maintained.

"We've dealt with 15 agents, including tax law specialists -- that's lawyers -- from four different offices, including (the) Treasury (Department) in Washington, D.C.," Sekulow said. "So the idea that this is a couple of rogue agents in Cincinnati is not correct."

Among the letters were several that bore return IRS addresses other than Cincinnati, including "Department of the Treasury / Internal Revenue Service / Washington, D.C.," and the signatures of IRS officials higher up the chain. Two letters with "Department of the Treasury / Internal Revenue Service / Washington, D.C." letterhead were signed by "Tax Law Specialist(s)" from Exempt Organizations Technical Group 1 and Technical Group 2. Lerner's signature, which appeared to be a stamp rather than an actual signature, appeared on a letter requesting additional information from the Ohio Liberty Council Corp.

Lerner has become one of the public faces of the controversy after refusing to testify before the House Oversight and Government Reform Committee last Wednesday, citing her Constitutional Fifth Amendment rights after reading a brief statement: "I have not done anything wrong. I have not broken any laws, violated IRS regulations or provided false information to this or any other committee."

That's her story and she's sticking to it.

Meanwhile, 3 different committees in Congress are apparently gearing up for hearings. This is exactly why a select committee is needed. The committees - including the Democratic controlled Senate Finance Committee - will probably work at cross purposes, obscuring rather than shedding much light on what traspired and who's responsible. Better to have the focus on one committee with one staff that will have subpoena power and the investigative resources to get to the bottom of the matter.

That won't happen. Boehner may want a select committee but the Democrats would never agree. So for the time being, we're going to have a busy month of June keeping track of the story and hope that Congress will eventually get its act together.