A jury convicted Thornton of 1st degree reckless homicide, party to a crime. On appeal he argued that Lee, one of the State’s witnesses, had perjured himself 10 years earlier in an unrelated, federal case. Thornton requested a new trial based on this newly-discovered evidence.
¶25 To be entitled to a new trial based on newly discovered evidence “a defendant must prove: ‘(1) the evidence was discovered after conviction; (2) the defendant was not negligent in seeking the evidence; (3) the evidence is material to an issue in the case; and (4) the evidence is not merely cumulative.’” State v. Plude, 2008 WI 58, ¶32, 310 Wis. 2d 28, 750 N.W.2d 42 (citation omitted). “If the defendant is able to prove all four of these criteria, then it must be determined whether a reasonable probability exists that had the jury heard the newlydiscovered evidence, it would have had a reasonable doubt as to the defendant’s guilt.” Id.
¶26 “A reasonable probability of a different result exists if there is a reasonable probability that a jury, looking at both the old and the new evidence, would have a reasonable doubt as to the defendant’s guilt.” Avery, 345 Wis. 2d 407, ¶25.
The court of appeals held that “new evidence that merely impeaches credibility of a witness is not a basis for a new trial on that ground alone.” See Greer v. State, 40 Wis. 2d 72, 78, 161 N.W.2d 255 (1968). Opinion, ¶30. It further held that evidence of Lee’s perjury would not have made a difference because at trial defense counsel had already impeached Lee’s credibility by attacking him with evidence of his 10 prior convictions and pointing out that he was motivated to lie to improve his situation at an upcoming sentencing hearing. Also, “there was more than sufficient evidence” to convict Thornton even without Lee’s testimony. Opinion, ¶¶33-35.