To find a defendant guilty but mentally ill, the jury must find that: (1) the defendant was guilty of the offense (2) the defendant was mentally ill at the time of the crime (3) the defendant was not legally insane. MCL 768.36(1); MSA 28.1059(1); People v. Phil Clark, 172 Mich App 1, 7; 432 NW2d 173 (1988). An instruction regarding a guilty but mentally ill verdict was warranted by the evidence in the instant case. First, defendant presented a diminished capacity defense, which falls within the definition of legal insanity. People v. Mangiapane, 85 Mich App 379, 395; 271 NW2d 240 (1978). Furthermore, Dr. O'Reilly testified that defendant was mentally ill. A criminal defendant is presumed to be competent to stand trial absent a showing that the defendant "is incapable because of his mental condition of understanding the nature and object of the proceedings against him or of assisting in his defense in a rational manner." MCL 330.2020(1); MSA 14.800(1020)(1); People v. Harris, 185 Mich App 100, 102; 460 NW2d 239 (1990). A defendant who is determined incompetent to stand trial shall not be proceeded against while he is incompetent." MCL 330.2022(1); MSA 14.800(1022)(1). The determination of a defendant's competence to stand trial is a matter within the discretion of the trial court. Harris, supra. However, a trial court has a duty to raise the issue of incompetence "where facts are brought to its attention which raise a 'bona fide doubt' as to the defendant's competence." Id. A trial court's decision with respect to whether a "bona fide doubt" exists is reviewed for an abuse of discretion. Id.