A defendant's conviction cannot stand based on false testimony, even if he did not challenge the testimony at the time of trial, and even when the Commonwealth made no attempt to cover it up. That is the result of the decision in Commonwealth Ware, decided by the SJC on July 26, 2019. In Darryene Ware's case, the defendant was convicted of murder based, in part, on testimony by a police officer that the defendant had given contradictory statements about where he was immediately prior to the murder. The officer testified that the defendant had initially told him that his friend had picked him up near a Dunkin Donuts, but that the defendant later changed his story and said he was picked up at his house. A recording of the interview showed that the Defendant had never said he was picked up near the Dunkin Donuts, and "pointedly denied on at least four occasions picked up there despite the police officers' questions and comments suggesting that he was."
The Commonwealth argued to the SJC that becasue the defendnat did not object to this tesimony or try to counter it at trial, the implication must be that there was a strategic reason he did not challenge it, and that as a result he should not be able to challenge it on appeal. The SJC acknowledged that there were some cases that suggested that was a rule, but held that "where the testimony is blatantly false and pertains to an issue central to the Commonwealth's case, a defendant's ability to discern thestatement's falsity does not absolve prosecutorsof theirdutyto correct."
There are a number of things to observe about this. First, even though the SCJ reached the right result, it still did it in terms of addressing the obligations of the prosecutor, rather than the rights of the Defendant. Too often the courts get wrapped up in the question about whether a police officer or a prosecutor acted malicously, and when the court (inevitably) finds that the police officer or the prosecutor may have just made a mistake, the court then denies any relief to the defendant. The better answer in a case like this would have been to simply say that whatever the obligations of the Commonwealth might have been, the Defendant has a right to a fair trial, and that one aspect of fairness is that the jury only hear evidence that is not demonstrably false. I quite doubt we will ever get there.
This case also illustrates the reason why talking to the police in the context of a criminal investigation is never a good idea. Look here -- the defendant "pointedly" and "repeatedly" denied the suggestions made by the police, but apparently that was not enough to stop the officer from testifying that he did, in fact, say something he did not say. Furhter, that was enough to satisfy a jury, and the defendant was convicted. Of murder. It is only because of the happenstance that the interview was recorded that the truth came out.
If you or someone you know is the subject of a police investigation, contact a lawyer before saying anyting to the police.