Bennie Starks (left) of Chicago spent 20 years in prison after being convicted of rape. DNA evidence pointed to another man, and charges against Starks were dropped May 15.

(AP) and [MORE] WASHINGTON - 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. Of these, 885 have profiles developed for the registry's website  exonerationregistry.org.

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 United States 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 newly opened National Registry of Exonerations.

Counties such as San Bernardino in California and Bexar County in Texas are heavily populated, yet seemingly have no exonerations, a circumstance that the academics say cannot possibly be correct.

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.

Regarding the 1,170 additional defendants who were left out of the registry, "we have only sketchy information about most of these cases," the report said. "Some of these group exonerations are well known; most are comparatively obscure. We began to notice them by accident, as a byproduct of searches for individual cases."

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.

"It used to be that almost all the exonerations we knew about were murder and rape cases. We're finally beginning to see beyond that. This is a sea change," said Gross.

Exonerations often take place with no public fanfare and the 106-page report that coincides with the opening of the registry explains why.

The leading causes of wrongful convictions include perjury, flawed eyewitness identification and prosecutorial misconduct. For those who have placed unequivocal faith in the US criminal justice system and believe that all condemned prisoners are guilty of the crime of which they were convicted, the data must make for a rude awakening.

"The most important thing we know about false convictions is that they happen and on a regular basis … Most false convictions never see the light of the day," said University of Michigan law professors Samuel Gross and Michael Shaffer, who wrote the study.

"Nobody had an inkling of the serious problem of false confessions until we had this data," said Rob Warden, executive director of the Center on Wrongful Convictions at Northwestern University. 

The unveiling of the exoneration registry comes days after a groundbreaking study from Columbia law school Professor James Liebman and 12 students. Published in the Columbia Human Rights Law Review, the study describes how Texas executed an innocent man named Carlos DeLuna in 1989. DeLuna was put to death for the 1983 murder of Wanda Lopez, a young woman, at a gas station. Carlos Hernandez, who bragged about committing the murder and bore a striking resemblance to DeLuna, was named at trial by DeLuna's defence team as the actual perpetrator of the crime. But DeLuna's false conviction is merely the tip of the iceberg, as the database suggests.

Recently also, Charlie Baird, a Texas judge, was prepared to issue an order posthumously exonerating Cameron Todd Willingham, who was executed in 2004 for the 1991 arson-related deaths of his three young daughters. Based upon "overwhelming, credible and reliable evidence", Baird concluded Willingham had been wrongfully convicted; this in addition to a jailhouse witness who recanted his testimony, and scientists who challenged the evidence at trial that the fire that destroyed the Willingham home was caused by arson. Baird was blocked by a state appeals court from issuing the order before he left the bench to pursue private practice.

And again in Texas, lawyers for Kerry Max Cook, a former death row prisoner who was wrongfully convicted of a 1977 murder in East Texas, claim that the district attorney in the case withheld in his possession the murder weapon and biological evidence in the case.

In 2012, the American death penalty has reached a crossroads. Public support for executions has decreased over the years, with capital punishment critics citing its high cost, failure to deter crime, and the fact that the practice places the nation out of step with international human rights norms. Last year, the US ranked fifth in the world in executions, a member of a select club of nations that includes China, Saudi Arabia, Iraq and Iran. Further, in the US states that have repealed the death penalty in recent years – including New Mexico, New Jersey, Illinois and, most recently, Connecticut – the killing of the innocent has been cited as a pivotal factor in favor of abolition.

Meanwhile, thanks to an EU embargo on lethal injection drugs to the US, states that practice capital punishment are faced with a shortage of poison to execute prisoners. Some have resorted to purchasing unapproved drug supplies on the black market, or using different chemicals altogether. For example, Ohio has abandoned its three-drug protocol for executions in favor of a single drug called pentobarbital, a barbiturate used to euthanize animals. And Missouri has decided to execute prisoners using propofol, a surgical anesthetic implicated in Michael Jackson's death.

Apparently desperate and lacking in options to kill, these states would be better-served by joining the civilized world and devoting their efforts to end the death penalty, rather than find new methods to satisfy their bloodlust – which, as the new evidence makes abundantly clear, cannot but cause them to execute innocent citizens. According to the Death Penalty Information Center, 140 men and women have been released from death row since 1973 due to innocence. That death row inmates are exonerated much more often than other categories of prisoner – even when a person's life is at stake – should shatter anyone's faith in the presumed infallibility of the court system.

It is now transparent to the public that, at best, the application of the death penalty is rife with human error and incompetence. At worst, we know there is prosecutorial misconduct: that the courts shelter and nurture officials who are rewarded for gaming the system by career advancement, rather than determining true guilt or innocence and ensuring that justice is done.