When will a judge order a present sanity hearing for a defendant?

"Both federal due process and state law require a trial judge to suspend trial proceedings and conduct a competency hearing whenever the court is presented with substantial evidence of incompetence, that is, evidence that raises a reasonable or bona fide doubt concerning the defendant's competence to stand trial. ( [Pen. Code,] 1368 ; Drope v. Missouri [ (1975) ] 420 U.S. [162,] 181 [95 S.Ct. 896, 43 L.Ed.2d 103].)" ( People v. Rogers (2006) 39 Cal.4th 826, 847, 48 Cal.Rptr.3d 1, 141 P.3d 135 ( Rogers ).) " [A]bsent a showing of "incompetence" that is "substantial" as a matter of law, the trial judge's decision not to order a competency hearing is entitled to great deference, because the trial court is in the best position to observe the defendant during trial. " ( People v. Sattiewhite (2014) 59 Cal.4th 446, 465, 174 Cal.Rptr.3d 1, 328 P.3d 1 ( Sattiewhite ).) "Whether to order a present sanity hearing is for the discretion of the trial judge, and only where a doubt as to sanity may be said to appear as a matter of law or where there is an abuse of discretion may the trial judge's determination be disturbed on appeal." ( People v. Pennington , supra , 66 Cal.2d at p. 518, 58 Cal.Rptr. 374, 426 P.2d 942.)

On appeal, our task is to examine "the inferences that were to be drawn from the undisputed evidence" and to ask "whether, in light of what was then known, the failure to make further inquiry into petitioner's competence to stand trial, denied him a fair trial." ( Drope v. Missouri , supra , 420 U.S. at pp. 174175, 95 S.Ct. 896 ( Drope ).) The focus of our inquiry is the evidence that "was in fact part of the record presented or otherwise made available to the trial

[5 Cal.5th 270]