Tax determination for fraud requires a show cause notice and payment of tax, interest and a substantial penalty to conclude proceedings. Where tax short payment, non payment, erroneous refund or wrongful input tax credit arises from fraud, wilful misstatement or suppression of facts, the proper officer must serve a show cause notice requiring payment of tax, interest and a penalty equivalent to the tax; supplementary statements may extend coverage for matching grounds; voluntary or timely payment at reduced penalty levels can conclude proceedings; the officer determines tax, interest and penalty and issues an order within the statutory limitation period, and conclusions under this section do not preclude prosecution proceedings.