Conn. Gen. Stat. § 12-263t

(2) Except in the case of a wilfully false or fraudulent return with intent to evade the tax or fee, no assessment of additional tax or fee shall be made after the expiration of more than three years from the date of the filing of a return or from the original due date of a return, whichever is later. Where, before the expiration of the period prescribed under this subsection for the assessment of an additional tax or fee, a taxpayer has consented, in writing, that such period may be extended, the amount of such additional tax due may be determined at any time within such extended period. The period so extended may be further extended by subsequent consents, in writing, before the expiration of the extended period.

(b) (1) The commissioner may enter into an agreement with the Commissioner of Social Services delegating to the Commissioner of Social Services the authority to examine the records and returns of any taxpayer subject to any tax or fee imposed under section 12-263q or 12-263r and to determine whether such tax has been underpaid or overpaid. If such authority is so delegated, examinations of such records and returns by the Commissioner of Social Services and determinations by the Commissioner of Social Services that such tax or fee has been underpaid or overpaid shall have the same effect as similar examinations or determinations made by the commissioner.

(2) The commissioner may enter into an agreement with the Commissioner of Social Services in order to facilitate the exchange of returns or return information necessary for the Commissioner of Social Services to perform his or her responsibilities under this section and to ensure compliance with the state's Medicaid program.

(3) The Commissioner of Social Services may engage an independent auditor to assist in the performance of said commissioner's duties and responsibilities under this subsection. Any reports generated by such independent auditor shall be provided simultaneously to the department and the Department of Social Services.

(c) (1) The commissioner may require all persons subject to a tax or fee imposed under section 12-263q or 12-263r to keep such records as the commissioner may prescribe and may require the production of books, papers, documents and other data, to provide or secure information pertinent to the determination of the taxes or fees imposed under section 12-263q or 12-263r and the enforcement and collection thereof.

(2) The commissioner or any person authorized by the commissioner may examine the books, papers, records and equipment of any person liable under the provisions of this section and may investigate the character of the business of such person to verify the accuracy of any return made or, if no return is made by the person, to ascertain and determine the amount required to be paid.

(d) The commissioner may adopt regulations, in accordance with the provisions of chapter 54, to implement the provisions of sections 12-263q to 12-263x , inclusive.