It is unlawful for any person liable for the tax under Chapter 6.15 to fail or refuse to secure the license required under this Chapter, to make the returns when required, or to fail to pay the license fee or tax when due, or for any person to make any false or fraudulent application or return or any false statement or return or any false statement or representation in, or in connection with, any application or return, or to aid or abet another in an attempt to evade payment of the fee or tax, or any part thereof, or for any person to fail to appear and/or testify in response to subpoena issued pursuant hereto, or to testify falsely upon any investigation of the correctness of a return, or upon the hearing of any appeal, or in any manner to hinder or delay the city of Pullman or any of its officers in carrying out the provisions of this Chapter and Chapter 6.15. (Ord. 92-9 §3, 1992. Formerly 6.02.160).