Institutio Oratoria
Quintilian
Quintilian. Institutio Oratoria, Volume 1-4. Butler, Harold Edgeworth, translator. Cambridge, Mass; London: Harvard University Press, William Heinemann Ltd., 1920-1922.
On the other hand in the case of a witness who is reluctant to tell the truth, the essential for successful examination is to extort the truth against his will This can only be done by putting questions which have all the appearance of irrelevance. If this he done, he will give replies which he
For just as in a set speech we usually collect detached arguments which in themselves seem innocuous to the accused, but taken together prove the case against him, so we must ask the reluctant witness a number of questions relative to acts antecedent or subsequent to the case, places, dates, persons, etcetera, with a view to luring him into some reply which will force him to make the admissions which we desire or to contradict his previous evidence.
If this fails, we must content ourselves with making it clear that he is reluctant to tell what he knows, and lead him with a view to tripping him up on some point or other, even though it be irrelevant to the case; we must also keep him in the witness-box for an unusual length of time, so that by saying everything that can be said and more than is necessary on behalf of the accused, he may be rendered suspect to the judge. Thus he will do the accused no less harm than if he had told the truth against him.
But if (to proceed to our second supposition) the advocate does not know what the intentions of the witness may be, he must advance gradually inch by inch and sound him by examination and lead him step by step to the particular reply which it is desired to elicit.
But since these witnesses are sometimes so artful that their first replies are designed to meet the wishes of the questioner, in order to win all the greater credit when subsequently they answer in a very different way, it will be the duty of the advocate to dismiss