In People v. Thomas, 178 Ill. 2d 215, 227 Ill. Dec. 410, 687 N.E.2d 892 (1997), a prior inconsistent statement of a witness was admitted as substantive evidence where the witness had no personal knowledge of the subject matter. Thomas, 178 Ill. 2d at 234. However, our supreme court reviewed any error surrounding the admission of the statement under the plain error doctrine and did not analyze whether the statement was admissible under section 115-10.1. Thomas, 178 Ill. 2d at 235. In Thomas, during trial, defense counsel failed to specifically object and argue that the witness whose prior inconsistent statement had been admitted lacked the requisite personal knowledge. The defendant also failed to raise this issue in a posttrial motion. See Thomas, 178 Ill. 2d at 234. Accordingly, the supreme court considered the issue waived and addressed any error of the admission of the statement under the plain error doctrine. Thomas, 178 Ill. 2d at 235. After viewing the evidence as a whole, the supreme court noted that the evidence as to the defendant's guilt was overwhelming, and therefore, the admission of the statement did not deprive the defendant of a fair trial. Thomas, 178 Ill. 2d at 235-36.