The Legal Profession Blog is reporting today on a recent case in which the New Jersey Appellate Division has reversed a a conviction because, among other reasons, the prosecutor had improperly vouched for the credibility of a police officer during summation. The case is State v Murphy and it is available here.
In this case, defense counsel attacked the police officer's credibility by arguing that his version of the events was incredible. Defense counsel suggested that noone would have done what the police officer claimed the defendant did (approach two people who were clearly identified as police and drop coccaine right in front of them). In reponse to those comments, the prosecutor stated during his summation that the police officer had no incentive to lie, a statement to which defense counsel promptly objected.
The court held that stating to the jury that the police have no incentive to lie is a statement of the very same character as those the New Jersey Supreme Court has deemed improper.