(a) The commissioner shall, not later than three years after the due date for the filing of a return or not later than three years after the date of receipt of such return by the commissioner, whichever period expires later, examine it and, in case any error is disclosed by such examination, shall, not later than thirty days after such disclosure, notify the taxpayer of such error. When it appears that any part of the deficiency for which a deficiency assessment is made is due to negligence or intentional disregard of the provisions of this chapter or regulations promulgated thereunder, there shall be imposed a penalty equal to ten per cent of the amount of such deficiency assessment, or fifty dollars, whichever is greater. When it appears that any part of the deficiency for which a deficiency assessment is made is due to fraud or intent to evade the provisions of this chapter or regulations promulgated thereunder, there shall be imposed a penalty equal to twenty-five per cent of the amount of such deficiency assessment. No taxpayer shall be subject to more than one penalty under this section in relation to the same tax period. Not later than thirty days after the mailing of such notice, the taxpayer shall pay to the commissioner, in cash or by check, draft or money order drawn to the order of the Commissioner of Revenue Services, any additional amount of tax shown to be due by the examination, or shall be paid by the State Treasurer, upon order of the Comptroller, any amount shown to be due it by such examination. The failure of the taxpayer to receive any notice required by this section shall not relieve the taxpayer of the obligation to pay the tax or any interest or penalties thereon. If, before the expiration of the time prescribed by this section for the examination of the return or the assessment of the tax, both the commissioner and the taxpayer consent in writing to such examination or assessment after such time, the return may be examined and the tax may be assessed at any time prior to the expiration of the period agreed upon. The period so agreed upon may be extended by subsequent agreements in writing made before the expiration of the period agreed upon. The commissioner may also in such a case extend the period during which a claim for refund may be made by such taxpayer.

(b) To any taxes which are assessed under this section, there shall be added interest at the rate of one per cent per month or fraction thereof from the date when the original tax became due and payable. The amount of any tax, penalty or interest due and unpaid under the provisions of this chapter may be collected under the provisions of § 12-35. The warrant therein provided for shall be signed by the commissioner or his authorized agent. The amount of any such tax, penalty or interest shall be a lien on the real estate of the taxpayer from the thirty-first day of December next preceding the due date of such tax until such tax is paid. The commissioner may, at any time after such December thirty-first, record such lien in the records of any town in which the real estate of such company is situated, but no such lien shall be enforceable against a bona fide purchaser or qualified encumbrancer of such real estate. When any tax with respect to which a lien has been recorded under the provisions of this section has been satisfied, the commissioner upon request of any interested party, shall issue a certificate discharging such lien, which certificate shall be recorded in the same office in which the lien was recorded. Any action for the foreclosure of such lien shall be brought by the Attorney General in the name of the state in the superior court for the judicial district in which the property subject to such lien is situated, or, if such property is located in two or more judicial districts, in the superior court for any one such judicial district, and the court may limit the time for redemption or order the sale of such property or make such other or further decree as it judges equitable.