26 CFR § 601.107 - Criminal investigation functions.
(a) General. Each district has a Criminal Investigation function whose mission is to encourage and achieve the highest possible degree of voluntary compliance with the internal revenue laws by: Enforcing the statutory sanctions applicable to income, estate, gift, employment, and certain excise taxes through the investigation of possible criminal violations of such laws and the recommendation (when warranted) of prosecution and/or assertion of the 50 percent ad valorem addition to the tax; developing information concerning the extent of criminal violations of all Federal tax laws (except those relating to alcohol, tobacco, narcotics, and firearms); measuring the effectiveness of the investigation process; and providing protection of persons and of property and other enforcement coordination as required.
(b) Investigative procedure.
(1) A witness when questioned in an investigation conducted by the Criminal Investigation Division may have counsel present to represent and advise him. Upon request, a copy of an affidavit or transcript of a question and answer statement will be furnished a witness promptly, except in circumstances deemed by the Regional Commissioner to necessitate temporarily withholding a copy.
(2) A taxpayer who may be the subject of a criminal recommendation will be afforded a district Criminal Investigation conference when he requests one or where the Chief, Criminal Investigation Division, makes a determination that such a conference will be in the best interests of the Government. At the conference, the IRS representative will inform the taxpayer by a general oral statement of the alleged fraudulent features of the case, to the extent consistent with protecting the Government's interests, and, at the same time, making available to the taxpayer sufficient facts and figures to acquaint him with the basis, nature, and other essential elements of the proposed criminal charges against him.
(c) Processing of cases after investigation. The Chief, Criminal Investigation Division, shall ordinarily notify the subject of an investigation and his authorized representative, if any, when he forwards a case to the Regional Counsel with a recommendation for prosecution. The rule will not apply if the case is with a United States Attorney.