RSA 87:6 — Returns and Extensions. –

I. The executor or administrator of the estate of every decedent whose death gives rise to a tax liability under this chapter shall, within the time prescribed by the Internal Revenue Service to file a federal estate tax return, file a return with the commissioner of revenue administration. The commissioner of revenue administration shall adopt rules, pursuant to RSA 541-A, relative to the form of such return and the data which it must contain for the correct computation of the New Hampshire estate tax. All returns shall be signed by the administrator or executor and the return preparer if other than the administrator or executor, subject to the pains and penalty of perjury.
II. It shall be the duty of the legal representative of the estate of any decedent who was a resident of this state at the time of his death and whose estate may be subject to the payment of a United States estate tax to attach a duplicate copy of the United States estate tax return as filed with the Internal Revenue Service to the return required by paragraph I.
III. For good cause, the commissioner may extend the time within which a taxpayer is required to file a return, and if such return is filed during the period of extension, no penalty for the failure to file under RSA 21-J:31 shall be imposed, but the executor or administrator shall be liable for interest as prescribed in RSA 21-J:28. An extension of time for filing a return shall not extend the time for the payment of the taxes due under this chapter. Failure to file the return within the period of the extension shall void such extension.
IV. When the commissioner has reason to believe that an executor or administrator has failed to file a return or include any part of the taxable property in a filed return, the commissioner may require the executor or administrator to file a return or a supplementary return showing such additional information as the commissioner prescribes. Upon receipt of the supplementary return, or if none is received within the time set by the commissioner, the commissioner may find and assess the amount due upon the information that is available. The making of such returns by the commissioner shall not relieve the executor or administrator of any penalty for the failure to make a correct original return or relieve them from the liability for interest imposed under RSA 21-J:28 or any other additional charges imposed by the commissioner.
V. The failure to file returns, the filing of fraudulent returns or the making, causing to be made or permitting to be made any false entry in the books or records of the estate with the intent to defraud the state or to evade the payment of the tax or any part thereof shall subject the executor or administrator to the penalties provided in RSA 21-J for such actions.