WASHINGTON (AP) - More than 2,000 people who were falsely convicted of serious crimes have been exonerated in the United States in the past 23 years, according to a new archive compiled at two universities.
There is no official record-keeping system for exonerations of convicted criminals in the country, so academics set one up. The new national registry, or database, painstakingly assembled by the University of Michigan Law School and the Center on Wrongful Convictions at Northwestern University School of Law, is the most complete list of exonerations ever compiled.
The database compiled and analyzed by the researchers contains information on 873 exonerations for which they have the most detailed evidence. The researchers are aware of nearly 1,200 other exonerations, for which they have less data.
They found that those 873 exonerated defendants spent a combined total of more than 10,000 years in prison, an average of more than 11 years each. Nine out of 10 of them are men and half are African-American.
Nearly half of the 873 exonerations were homicide cases, including 101 death sentences. Over one-third of the cases were sexual assaults.
DNA evidence led to exoneration in nearly one-third of the 416 homicides and in nearly two-thirds of the 305 sexual assaults.
Researchers estimate the total number of felony convictions in the U.S. is nearly a million a year.
The overall registry/list begins at the start of 1989. It gives an unprecedented view of the scope of the problem of wrongful convictions in the United States and the figure of more than 2,000 exonerations "is a good start," said Rob Warden, executive director of the Center on Wrongful Convictions.
"We know there are many more that we haven't found," added University of Michigan law professor Samuel Gross, the editor of the National Registry of Exonerations.
The registry excludes at least 1,170 additional defendants. Their convictions were thrown out starting in 1995 amid the periodic exposures of 13 major police scandals around the country. In all the cases, police officers fabricated crimes, usually by planting drugs or guns on innocent defendants.
In half of the 873 exonerations studied in detail, the most common factor leading to false convictions was perjured testimony or false accusations. Forty-three percent of the cases involved mistaken eyewitness identification, and 24 percent of the cases involved false or misleading forensic evidence.
In two out of three homicides, perjury or false accusation was the most common factor leading to false conviction. In four out of five sexual assaults, mistaken eyewitness identification was the leading cause of false conviction.
Seven percent of the exonerations were drug, white-collar and other nonviolent crimes, 5 percent were robberies and 5 percent were other types of violent crimes.