Anyone, under the right conditions, can falsely confess to a crime, but those most prone to this are young people, the mentally slow, and arrestees terrified of the police. False confessors often think that the investigators will eventually catch the real criminal and everything will be straightened out. These people obviously don't know much about law enforcement and the criminal justice system.
An interrogator more interested in getting at the truth than acquiring a confession should suspect that something is wrong when the physical evidence contradicts the confessor's account of the crime. Factual inconsistency within the confession is another sign of trouble. To avoid false confessions, interrogators should be careful not to feed details of the crime to suspects. Interrogators should also ask open ended questions. Contradictions in confessions should be resolved before the written statements are signed. To reduce the risk of coercion, prolonged questioning should be avoided, and only one officer should conduct the interrogation in a calm and professional manner. Ideally, an interrogator should only try to acquire a confession when there is substantial evidence of guilt. Interrogation techniques should not be used on weak suspects.
All interrogations should be video-taped (In some states this is required by law.) and no conviction should be based solely on the strength of a confession.
The Juan Rivera Case
On the night of August 17, 1992, someone raped and stabbed to death an 11-year-old girl named Holly Staker who was baby-sitting two young children in Waukegan, Illinois. The Lake County police questioned 200 people, including a 19-year-old with a ninth-grade education named Juan Rivera. Rivera said he had attended a party that night not far from the murder house. At the party he had noticed a man who had behaved strangely. Weeks later, on October 27, 1992, the police brought Rivera back to the station for a second interview. Rivera told the same story, but the interrogators didn't believe him.
Following a psychologically brutal, nonstop 24-hour interrogation, Rivera broke down and confessed to raping and murdering Holly Staker. When asked why his fingerprints were not at the scene of the crime, Rivera provided a helpful explanation. After stabbing the girl 27 times, then raping her, Rivera said he bashed in a door with a mop to simulate a break and entering. Before leaving the house, he removed his fingerprints by wiping off the mop handle with a towel. He then broke the murder knife and tossed the pieces in the victim's backyard.
In 1993, a jury found Rivera guilty and sentenced him to life. In two subsequent trials, the last being in 2009, juries found him guilty again even though DNA testing in 2005 ruled him out as the depositor of the semen inside the victim's body. (The prosecutor wished this exonerating evidence away with the preposterous theory that the 11-year-old had had sex with another man just before being murdered by Rivera.) The fact Rivera had been convicted of such a serious crime without the benefit of physical evidence linking him to the crime scene or the murder weapon revealed the power Rivera's confessions had over the jurors.
On December 10, 2011, an Illinois appellate court reversed Rivera's murder conviction. The judge also barred Lake County prosecutors from trying Rivera for the fourth time. A week later, the 39-year-old, after 19 years served at the Statesville Correctional Center near Joilet, walked out of prison. Because Rivera's interrogators manufactured a false confession, Holly Staker's killer has not been brought to justice.