Can a jury who had been convicted of first degree murder with special circumstances, then convicted of arson, be impartial on the same charge?

Appellant claims that this procedure violated his right to an impartial jury on the arson charge. The jury which had just convicted him of first degree murder with special circumstances could not have been an impartial fact finder when it then considered his guilt of arson. (See People v. Haskett (1982) 30 Cal.3d 841, 867, 180 Cal.Rptr. 640, 640 P.2d 776.) Since the penalty jury is not required to prepare written findings or disclose what aggravating and mitigating factors were found to be true and to have been relied on, it is not possible to determine what influence the arson charge had on the jury's decision. For all we know, the arson could have been the determinative factor or even the only aggravating factor the jury relied on. (See infra, at p. 769 of 187 Cal.Rptr., at pp. 1296-1297 of 654 P.2d.)