§ 144.670 RSMo — Additional assessment made when, notice

If the director is not satisfied with the return payment of tax made by any taxpayer, he shall make an additional assessment based upon the facts contained in any returns or upon any information in his possession, and the director shall give the taxpayer written notice in person or by certified mail of the amount of the additional tax. The director may only base an additional assessment upon an estimate of the taxpayer's liability under sections 144.600 to 144.748 , if:

(1) The taxpayer fails to file a return; or

(2) The taxpayer's books and records are incomplete or illegible in the opinion of the director when conducting an examination of the accuracy of any return filed by the taxpayer; or

(3) The taxpayer denies the director access to the taxpayer's books and records for the purpose of conducting an examination of the accuracy of any return filed by the taxpayer.