What is the evidence of misconduct by a juror at a murder trial?

No such abuse appears here. The sole evidence of the alleged misconduct was the declaration of a defense investigator that purports to relate a conversation with the juror. It is settled, however, that "a jury verdict may not be impeached by hearsay affidavits." ( People v. Villagren, supra, 106 [45 Cal.3d 1319] Cal.App.3d at p. 729, 165 Cal.Rptr. 470; accord, People v. Spelio (1970) 6 Cal.App.3d 685, 690, 86 Cal.Rptr. 113.) ⁵

Defendant contends the court erred under People v. Murtishaw (1981) 29 [756 P.2d 251] Cal.3d 733, 175 Cal.Rptr. 738, 631 P.2d 446, when over defense objection it permitted an expert to testify about defendant's future dangerousness and to give an opinion that he could kill again.