Rule 405 - Methods of Proving Character(a) Reputation. In all cases in which evidence of character or a trait of character of a person is admissible, proof may be made by testimony as to reputation. On cross-examination, inquiry is allowable into relevant specific instances of conduct. (b) Specific instances of conduct. In cases in which character or a trait of character of a person is an essential element of a charge, claim, or defense, proof may also be made of specific instances of his conduct.