¶30. With due process as our touchstone, we conclude that when a defendant seeks to suppress witness statements as the product of coercion, the police misconduct must be more than that set forth in Clappes. It must be egregious such that it produces statements that are unreliable as a matter of law. The coercion must be egregious because, as we have shown, it is typically ‘egregious’ police misconduct that offends due process. Our concern is with police misconduct that, by its nature, undermines confidence in the reliability of a witness’s statements. Witness statements obtained by police methods that induce lying have no place in our system of justice because a conviction based on unreliable evidence undermines the fundamental fairness of a defendant’s trial. In short, due process demands that the State not marshal its resources against an accused in a manner that results in a conviction based on unreliable evidence obtained through egregious police practices.
¶31. Upon an examination of the case law and the parties’ arguments, we glean several factors to consider in determining whether police misconduct is egregious such that it produces statements that are unreliable as a matter of law. These factors include (1) whether a witness was coached on what to say; (2) whether investigating authorities asked questions blatantly tailored to extract a particular answer, see Gonzales, 164 F.3d at 1289; (3) whether the authorities made a threat with consequences that would be unlawful if carried out, see United States v. Tingle, 658 F.2d 1332, 1335-36 (9th Cir. 1981); (4) whether the witness was given an express and unlawful quid pro quo; (5) whether the State had a separate legitimate purpose for its conduct, Tingle, 658 F.2d at 1337; and, (6) whether the witness was represented by an attorney at the time of the coercion or statement, see Merkt, 764 F.2d at 269. The presence of the first four factors weighs in favor of suppression while the presence of the second two factors weighs against it. Application of these and other relevant factors will help to ensure that it is unreliable evidence that is suppressed. It will also help to guarantee that the State does not obtain convictions based on practices that offend fundamental fairness.
¶32. In cases where an application of the factors results in a determination that witness statements at issue will not be suppressed, the defendant nevertheless retains the ability to test the credibility of the witness statements through, among other approaches, cross-examination before the jury. SeeNerison, 136 Wis. 2d at 45. Cross-examination is an essential tool for “sifting the conscience of the witness” and thereby protecting a defendant’s rights at trial. State v. Bauer, 109 Wis. 2d 204, 208 n.3, 325 N.W.2d 857 (1982) (citing Mattox v. United States, 156 U.S. 237, 242-43 (1895)). The jury, of course, has the duty to scrutinize and weigh the testimony of witnesses and to determine the effect of the evidence as a whole. See Hampton v. State, 92 Wis. 2d 450, 462, 285 N.W.2d 868 (1979); Wis JI–Criminal 300.5 These safeguards–cross-examination and the jury’s role in weighing the evidence–help ensure a fair trial where due process does not require the suppression of witness statements.”
But see State v. Daniels, KS SCt NO. 87,790, 6/25/04 (“To determine whether a witness’ statements are voluntary, the court looks at the totality of the circumstances and considers the same factors used to weigh the voluntariness of a defendant’s confession.”).