Proffer agreement
In U.S. criminal law, a proffer agreement, proffer letter, proffer, or "Queen for a Day" letter is a written agreement between a prosecutor and a defendant or prospective witness that allows the defendant or witness to give the prosecutor information about an alleged crime, while limiting the prosecutor's ability to use that information against him or her.[3] A proffer does not ensure immunity; however, it often involves a deal for leniency.For instance, a defendant might secure a recommendation for a lighter sentence or other significant advantages in return for providing valuable and truthful information.[4] Although the statement from the proffer agreement may not be used by the prosecutors, it often results in discovery of new evidence, which then may be used.For this reason, many defendants are reluctant to engage in a proffer agreement.