In People v. Wise, 205 Ill. App. 3d 1097, 150 Ill. Dec. 930, 563 N.E.2d 1057 (1990), before trial, the eyewitness signed two statements which stated that defendant was not involved in the robbery. The eyewitness disavowed both statements and claimed that he did not know what he signed. At trial, the witness testified that defendant grabbed him from behind in a bear hug while another man grabbed the victim's gold chain. On appeal, the court noted that although the testimony of a single witness, if positive and credible, even if contradicted, is sufficient to support a conviction, in Wise, the testimony of the eyewitness did not merely contain minor discrepancies but was severely impeached by inconsistencies and lack of corroborative evidence.