"A statement that, hypothetically, reflected on the complaining witness's credibility or the strength of the proof would be gratuitous and improper." Prof. Stephen Gillers, "People v. DSK: What Should Vance Say," Legal Ethics Forum.
“The complainant was untruthful with us in nearly every substantive interview. She was untruthful about matters great and small in significance.” Assistant District Attorney Joan Illuzzi-Orbon, to the court on Tuesday.
From the prosecutor's motion to dismiss ( PDF):
At the time of the indictment, all available evidence satisfied us that hte complainant was reliable. But evidence gathered in our post-indictment investigation severely undermind her realiability as a witness in this case. That an individual has lied in the past or committed criminal acts does not necessarilly render the unbelievable to us as prosecutors, or keep us from putting themo n the witness stand at trial. But the nature and number of the complainant's falsehoods leave us unable to credit her version of events beyond a reasonable doubt, whatever the truth may be about the encounter between the complainant and the defendant. If we do not believe her beyond a reasonable doubt, we cannot ask a jury to do so.