In Griggs v. Board of Trustees (1964) 61 Cal. 2d 93 37 Cal. Rptr. 194, 389 P.2d 722, our Supreme Court held that combining investigative and adjudicative functions in an administrative proceeding does not, by itself, constitute a denial of due process. (Id. at p. 98.) Further, in Burrell v. City of Los Angeles (1989) 209 Cal. App. 3d 568 257 Cal. Rptr. 427, Division Five of this court held that certain provisions of the charter of the City of Los Angeles did not violate federal or state due process requirements. "The Supreme Court has found that allowing a single decisionmaker to undertake both the investigative and the adjudicative functions in an administrative proceeding does not, by itself, constitute a denial of due process. (Griggs v. Board of Trustees, supra, 61 Cal. 2d at p. 98 . . . .)" (Id. at pp. 581-582.) Rather, as in the federal courts, our Supreme Court requires a party seeking to show bias or prejudice on the part of an administrative decision maker to prove the same with concrete facts: " 'Bias and prejudice are never implied and must be established by clear averments.' Indeed, a party's unilateral perception of an appearance of bias cannot be a ground for disqualification unless we are ready to tolerate a system in which disgruntled or dilatory litigants can wreak havoc with the orderly administration of dispute-resolving tribunals." (Andrews v. Agricultural Labor Relations Bd. (1981) 28 Cal. 3d 781, 792 171 Cal. Rptr. 590, 623 P.2d 151; accord, Gill v. Mercy Hospital (1988) 199 Cal. App. 3d 889, 910-911 245 Cal. Rptr. 304; American Isuzu Motors, Inc. v. New Motor Vehicle Bd. (1986) 186 Cal. App. 3d 464, 472-473 230 Cal. Rptr. 769.) The court added, "Our courts have never required the disqualification of a judge unless the moving party has been able to demonstrate concretely the actual existence of bias. We cannot now exchange this established principle for one as vague, unmanageable and laden with potential mischief as an 'appearance of bias' standard, despite our deep concern for the objective and impartial discharge of all judicial duties in this state. The foregoing considerations, of course, are equally applicable to the disqualification of a judicial officer in the administrative system. Indeed, the appearance of bias standard may be particularly untenable in certain administrative settings." (Andrews v. Agricultural Labor Relations Bd., supra, 28 Cal. 3d at pp. 793-794, fn. omitted.) In a footnote, the court observed that there were some situations in which a decision maker should be disqualified because of the "probability" of bias, such as when the decision maker has a personal or financial interest in the outcome, or is either familially or professionally related to the litigant. (Id. at p. 793, fn. 5.) "Thus, it appears that the highest court of this state construes the state Constitution's due process guaranty of a fair and impartial administrative decisionmaker in the same manner as the federal courts have interpreted parallel provisions in the federal Constitution. In other words, mere involvement in ongoing disciplinary proceedings does not, per se, violate due process principles.Conversely, those principles are violated . . . if the official or officials who take part in the proceedings are demonstrably biased or if, in the least, circumstances such as personal or financial interest strongly suggest a lack of impartiality. Our Supreme Court has emphatically rejected the notion that a subjective 'appearance of bias' is enough to taint an entire legislatively created system of handling disciplinary matters." (Burrell v. City of Los Angeles, supra, 209 Cal. App. 3d at p. 582.)