Bulletin: National Registry of Exonerations Report for 2015: (Part Two): False Confessions: A record year: "A record 27 exonerations in 2015 were convictions based on false confessions, and more than 80% of them were homicides. Twenty-two of the 27 false confession exonerations in 2015 were homicides – 39% of all homicide exonerations in 2015 – more than any previous year. Most of the homicide exonerees who falsely confessed were less than 18 years old or suffered from mental illness or intellectual disability or both (13/22)."

"False confessions: A record 27  exonerations in 2015 were convictions based on false confessions, and more than 80% of them were homicides. Twenty-two of the 27 false confession exonerations in 2015 were homicides – 39% of all homicide exonerations in 2015 – more than any previous year Most of the homicide exonerees who falsely confessed were less than 18 years old or suffered from mental illness or intellectual disability  or both (13/22). For example: In 2006, Bobby Johnson, a barely-literate 16-year-old with an IQ of 69, was interrogated by two New Haven, Connecticut detectives about the murder of Herbert Fields. The detectives told Johnson (falsely) that they had physical evidence tying him to the murder and that he would face the death penalty if convicted (also a lie).  They promised him probation if he confessed. Johnson did confess and was convicted and sentenced to 38 years. He was exonerated in 2015,  nine years later, after it was discovered that the police had concealed evidence that identified the real killer."
 http://www.law.umich.edu/special/exoneration/Documents/Exonerations_in_2015.pdf