As the scientific reliability of polygraph tests has not been established, testimony or other evidence relating to the results of such tests is not admissible to establish guilt or innocence absent a stipulation by both parties to admissibility.143 This prohibition extends to any procedure that is deemed to be the functional equivalent of a lie detector test.143.1 Similarly, polygraph evidence is never admissible to establish that a witness’ version of the events is true. These rules reflect a legitimate concern that jurors will assume that the results of the polygraph are accurate and will therefore accept the witness’ testimony as the truth. Put differently, the concern is that a potentially unreliable lie detector test will take the place of the jury in assessing the credibility of witnesses.143.2
Further, testimony that a criminal defendant refused to take a polygraph examination is inadmissible because it impinges upon a defendant’s right to remain silent.144 But where a criminal defendant makes a confession during, immediately after or as a result of a polygraph test and there is an issue as to whether the confession was voluntary, any witnesses testifying about the confession may refer to the polygraph examination, as the jury is entitled to consider all surrounding circumstances in determining voluntariness. The witness, however, may not refer to the results of that test.145 In such circumstances, at the very least, the trial court must apply enhanced scrutiny to assure that any references to a polygraph are necessary, of minimal prejudicial impact and that no other appropriate alternative evidence is available to establish the relevant operative fact sought to be admitted. The trial court must also formulate a clear cautionary instruction for the jury.145.1
143. State v. Cooke, 914 A.2d 1078, 1096 (Del. 2007); Capano v. State, 781 A.2d 556, 592 (Del. 2001); Melvin v. State, 606 A.2d 69, 71 (Del. 1992); Whalen v. State, 434 A.2d 1346, 1353 (Del. 1980), cert. denied, 455 U.S. 910 (1982); Thompson v. State, 399 A.2d 194, 198 (Del. 1979); Foraker v. State, 394 A.2d 208, 213 (Del. 1978); Williams v. State, 378 A.2d 117, 120 (Del. 1977), cert. denied, 436 U.S. 908 (1978); State v. Dyson, Cr. A. Nos. 1N87-12-1200FC-1201FC, slip op. at 8, Gebelein, J. (Del. Super. May 5, 1989).
143.1. Holtzman v. State, No. 221, 1997, slip op. at 12, Holland, J. (Del. July 27, 1998) (ORDER), disposition reported at 718 A.2d 528 (Del. 1998) (TABLE).
143.2. Capano v. State, 781 A.2d 556, 592 (Del. 2001).
144. Melvin v. State, 606 A.2d 69, 72 (Del. 1992); Duonnolo v. State, 397 A.2d 126, 132 (Del. 1978).
145. Whalen v. State, 434 A.2d 1346, 1353-54 (Del. 1980), cert. denied, 455 U.S. 910 (1982); Duonnolo v. State, 397 A.2d 126, 132 (Del. 1978); State v. Dyson, Cr. A. Nos. 1N87-12-1200FC-l201FC, slip op. at 8, Gebelein, J. (Del. Super. May 5, 1989).
145.1. Capano v. State, 781 A.2d 556, 593 (Del. 2001).
© 2010 David L. Finger