Example of a Case In Which Polygraph Test (Lie Detector) Was Admissible
Is polygraph test to determine circumstances surrounding statements to the police admissible ?
In People v. Jefferson, 184 Ill. 2d 486, 492, 705 N.E.2d 56, 59, 235 Ill. Dec. 443 (1998), the defendant sought to explain her inculpatory statement with testimony that the police had said her daughter (the victim) had only a few hours to live, and if she signed the statement she could see her daughter, talk to her parents, and go home.
In response the State, after a discussion with the trial judge outside the jury's presence, introduced testimony that defendant had agreed to take a polygraph test, a test was scheduled, and about 5 or 10 minutes later defendant told the officers that she wanted to tell the truth about what had happened.
Despite the general rule of exclusion, the supreme court held the evidence became admissible to explain the circumstances surrounding the defendant's inculpatory statement to police, after the defendant raised the contention in her testimony that her statement was induced by promises of lenient treatment. Jefferson, 184 Ill. 2d at 496, 705 N.E.2d at 61;
People v. Jackson, 198 Ill. App. 3d 831, 846, 556 N.E.2d 619, 629, 145 Ill. Dec. 1 (1990) (evidence that defendant failed polygraph examination admissible to show that failure motivated his confession, rather than threats by the police);
People v. Melock, 149 Ill. 2d 423, 465, 599 N.E.2d 941, 960, 174 Ill. Dec. 857 (1992) (although Jackson "gives us pause" ( Melock, 149 Ill. 2d at 463, 599 N.E.2d at 959), defendant was permitted to show polygraph examiner deceived him regarding his test results, leading him to confess).