The Shelby County District Attorney's office in Tennessee is reviewing all cases handled by five Memphis police officers charged in the beating and killing of Tyre Nichols. The officers were added to the county's list of law enforcement officers whose credibility has been questioned and the review includes both closed and pending cases. The review is an important step in ensuring justice for Tyre Nichols and his family, and is a reminder of the importance of holding law enforcement officers accountable for their actions.