Utah Code § 78B-1-128: Who may be witnesses -- Jury to judge credibility.

(1) All persons, without exception, otherwise than as specified in this part, who, having organs of sense, can perceive, and, perceiving, can make known their perceptions to others, may be witnesses.

(2) Neither parties nor other persons who have an interest in the event of an action or proceeding are excluded; nor those who have been convicted of crime; nor persons on account of their opinions on matters of religious belief.

(3) The credibility of a witness may be questioned by:

(a) the manner in which the witness testifies;

(b) the character of the witness testimony;

(c) evidence affecting the witness' character for truth, honesty, or integrity;

(d) the witness' motives; or

(e) contradictory evidence.

(4) The jury is the exclusive judge of credibility.