Canon CXXXII.
Canons of Local Councils Received in Trullo (Sardica, Carthage) · The Seven Holy Ecumenical Councils
Concerning a bishop who removes a man from communion who says he has confessed to the bishop alone his crime.
LocalT 2.136.2
It also seemed good that if on any occasion a bishop said that someone had confessed to him alone a personal crime, and that the man now denies it; let not the bishop think that any slight is laid upon him if he is not believed on his own word alone, although he says he is not willing to communicate with the man so denying through a scruple of his own conscience.
LocalT 2.136.3
If a bishop says “someone has confessed to me alone a crime,” if the someone denies it, he [i.e. the bishop] is not easily to be believed.
LocalT 2.136.6