It is unlawful for any person knowingly to make any material misrepresentation to any officer, employee or agency of the city in any official application to, or official dealing or negotiation with, the officer or agency; or to commit perjury before any tribunal or officer of the city; or to knowingly make any material misrepresentation to any law enforcement officer of the city concerning any facts or matters under investigation. (2001 Code § 134.07)