From “Exonerations in the United States 1989 through 2003” – Journal of Criminal Law and Criminology, Volume 95 Issue 2 (2005):
“In fifty-one of the 340 exonerations between 1989 and 2004-15 the defendants confessed to crimes they had not committed. In most of these cases it is apparent that the false confessions were coerced by the police. One defendant falsely confessed to larceny; nine falsely confessed to rape; and forty-one -80%- falsely confessed to murder… False confessions … are usually the product of long, intensive interrogations that eventually frighten or deceive or break the will of a suspect to the point where he will admit to a terrible crime that he did not commit. Some of these interrogations stretch over days and involve relays of police interrogators. ..
False confessions are heavily concentrated among the most vulnerable groups of innocent defendants. Thirty-three of the exonerated defendants were under eighteen at the time of the crimes for which they were convicted, and fourteen of these innocent juveniles falsely confessed – 42%, compared to 13% of older exonerees.
False confessions are even more prevalent among exonerees with mental disabilities. Our data indicate that sixteen of the 340 exonerees were mentally retarded; 69% of them-over two thirds-falsely confessed. ..Overall, 55% of all the false confessions we found were from defendants who were under eighteen, or mentally disabled, or both. Among adult exonerees without known mental disabilities, the false confession rate was 8%.”