Comparing special prosecutors to a “runaway grand jury” and deploring leak-driven, media-manipulated investigations, a former judge of the New York Court of Appeals on Monday said the increasing reliance on independent counsel threatens the governmental balance of powers while raising deep issues of fundamental fairness.

Joseph W. Bellacosa said a “fevered atmosphere of frontier-type justice” frequently accompanies the “modern day exhibitionism” of prosecutions conducted outside the traditional boundaries. He said prosecutorial excesses are more likely when the prosecutor is essentially a freelancer and the press is clamoring for action.