If any taxpayer fails to apply for license or make his return, or if the finance director is dissatisfied as to the correctness of the statements made in the application or return of any taxpayer, said officer or his authorized agent may enter the premises of such taxpayer at any reasonable time for the purpose of inspecting his books or records of account to ascertain the amount of the fee or tax or to determine the correctness of such statement, as the case may be, and examine any person under oath administered by said officer, or his agent, touching the matters inquired into, or said officer or his authorized agent may fix a time and place for an investigation of the correctness of the return and may issue a subpoena to the taxpayer or any other person to attend upon such investigation and there testify, under oath administered by said officer or his agent, in regard to the matters inquired into and may, by subpoena, require him or any person to bring with him such books, records, and papers as may be necessary. [Code 1980 at § 15.04.120].