Any individual may be licensed as a private investigator provided that he or she meets the following requirements:
(a) He or she is twenty-one years of age or older.
(b) He or she is a United States citizen or has declared an intent to become a citizen.
(c) He or she is able to read, write and speak the English language.
(d) He or she is clean in dress and person, of good moral character and not addicted to the use of intoxicating liquors or drugs.
(e) He or she is of sound physique, has good eyesight and not subject to vertigo, heart trouble or any other infirmity of body which might render him or her unfit for the safe carrying out of the duties of the private investigator.
(f) He or she has a good reputation for integrity, has not been convicted of a felony or any offense involving moral turpitude within the last twenty years, and is not suffering from any mental defect or disorder.