Conn. Gen. Stat. § 12-405k

(b) The commissioner or any agent of the commissioner authorized to conduct any inquiry, investigation or hearing hereunder may administer oaths and take testimony under oath relative to the matter of inquiry or investigation. At any hearing ordered by the commissioner, the commissioner or his agent authorized to conduct such hearing and having authority by law to issue such process may subpoena witnesses and require the production of books, papers and documents pertinent to such inquiry. No witness under subpoena authorized to be issued by the provisions of this section shall be excused from testifying or from producing books or papers on the ground that such testimony or the production of such books or other documentary evidence would tend to incriminate him, but such evidence or the books or papers so produced shall not be used in any criminal proceeding against him. If any person disobeys such process or, having appeared in obedience thereto, refuses to answer any pertinent question put to him by the commissioner or his authorized agent, or to produce any books and papers pursuant thereto, the commissioner or such agent may apply to the superior court for the judicial district wherein the taxpayer resides or wherein the business has been conducted, or to any judge of said court if the same is not in session, setting forth such disobedience to process or refusal to answer, and said court or such judge shall cite such person to appear before said court or such judge to answer such question or to produce such books and papers and, upon his refusal so to do, shall commit such person to a community correctional center until he testifies, but not for a period longer than sixty days. Notwithstanding the serving of the term of such commitment by any person, the commissioner may proceed in all respects with such inquiry and examination as if the witness had not previously been called upon to testify. Officers who serve subpoenas issued by the commissioner or under the authority granted by this section and witnesses attending hearings conducted by him hereunder shall receive fees and compensation at the same rates as officers and witnesses in the courts of this state, to be paid on vouchers of the commissioner on order of the Comptroller from the proper appropriation for the administration of this chapter.

(c) Any taxpayer aggrieved by the action of the commissioner or his authorized agent in fixing the amount of any tax, penalty or interest provided for by this chapter may apply to the commissioner, in writing, within sixty days after the notice of such action is delivered or mailed to such taxpayer, for a hearing and a correction of the amount of the tax, penalty or interest so fixed, setting forth the reasons why such hearing should be granted and the amount by which such tax, penalty or interest should be reduced. The commissioner shall promptly consider each such application and may grant or deny the hearing requested. If it is granted, the commissioner shall notify the applicant of the time and place fixed for such hearing. After such hearing the commissioner may make such order in the premises as appears to him just and lawful and shall furnish a copy of such order to the applicant. The commissioner may, by notice in writing, at any time within three years after the date when any return of any taxpayer has been due, order a hearing on his own initiative and require the taxpayer or any other individual whom he believes to be in possession of relevant information concerning the taxpayer to appear before him or his authorized agent with any specified books of account, papers or other documents, for examination under oath.
at any time within three years after the date when any return of any taxpayer has been due, order a hearing on his own initiative and require the taxpayer or any other individual whom he believes to be in possession of relevant information concerning the taxpayer to appear before him or his authorized agent with any specified books of account, papers or other documents, for examination under oath.

(d) Any taxpayer aggrieved because of any order, decision, determination or disallowance of the commissioner under the provisions of this chapter may, within one month after service upon the taxpayer of notice of such order, decision, determination or disallowance, make application in the nature of an appeal therefrom to the superior court for the judicial district of New Britain, which shall be accompanied by a citation to the commissioner to appear before said court. Such citation shall be signed by the same authority, and such appeal shall be returnable at the same time and served and returned in the same manner, as is required in case of a summons in a civil action. The authority issuing the citation shall take from the appellant a bond or recognizance to the state of Connecticut, with surety to prosecute the appeal to effect and to comply with the orders and decrees of the court in the premises. Such appeals shall be preferred cases, to be heard, unless cause appears to the contrary, at the first session, by the court or by a committee appointed by it. Said court may grant such relief as may be equitable and, if such tax has been paid prior to the granting of such relief, may order the Treasurer to pay the amount of such relief, with interest at the rate of nine per cent per annum, to the aggrieved taxpayer. If the appeal has been taken without probable cause, the court may tax double or triple costs, as the case demands; and, upon all such appeals which may be denied, costs may be taxed against the appellant at the discretion of the court, but no costs shall be taxed against the state.