Commonwealth v. Mooney

The witness Allen having testified to certain facts tending to prove the guilt of the defendant, it was not competent for the defendant to show what opinion the witness may have had or expressed upon the merits of the case. The fact that he had an opinion that the defendant was innocent would not tend to contradict or impeach him. At most, it only shows the weight he gave to the facts testified to by him as tending to prove the defendant’s guilt, which is for the jury exclusively, and upon which the opinion of witnesses is not competent.

Exceptions overruled.