A new study digs into the reasons people are wrongly convicted, and it has found that 54 percent of those defendants are victimized by official misconduct, with police involved in 34 percent of cases, prosecutors in 30 percent, and some cases involving both police and prosecutors. The study by the National Registry of Exonerations reviewed 2,400 exonerations it has logged between 1989 and 2019, nearly 80 percent of which were for violent felonies. Of the 2,400, 93 innocent defendants were sentenced to death and later cleared before they were executed. The study also found that police and prosecutors are rarely disciplined for actions that lead to a wrongful conviction. Researchers found that 4 percent of prosecutors involved in those convictions were disciplined, but the penalties were "comparatively mild" and only three were disbarred. Police officers were disciplined in 19 percent of cases leading to wrongful convictions, and in 80 percent of those cases officers were convicted of crimes, such as Chicago police Sgt. Ronald Watts, who led a group of officers who planted drug or gun evidence leading to 66 false convictions. The 2,400 cases are far from a comprehensive count, since there is no centralized national database of criminal cases at the state and local levels. So an estimate of how often wrongful convictions occur, as a percentage of overall cases, is not possible. The study acknowledges there are other areas to examine, including quantifying ineffective assistance by defense attorneys.