New Analysis: Innocent Death-Sentenced Prisoners Wait Longer than Ever for Exoneration

On July 1, after waiting 41 years for his name to be cleared, Larry Roberts became the 200^th person exonerated from death row. A new Death Penalty Information Center analysis finds that Mr. Roberts’ experience illustrates a troubling trend: for innocent death-sentenced prisoners, the length of time between wrongful conviction and exoneration is increasing. In the past twenty years, the average length of time before exoneration has roughly tripled, and 2024 has the highest-ever average wait before exoneration, at 38.7 years. Our research suggests that two of the factors contributing to this phenomenon are procedural rules restricting prisoner appeals and resistance by state officials to credible claims of innocence.

Our Innocence Database tracks people who were exonerated since 1973, after the Supreme Court’s decision in Furman v. Georgia invalidated the nation’s death penalty statutes and commuted the sentences of everyone on death row. The earliest death sentence in our database was in 1963. As a result, it makes sense that the average length of time before exoneration would increase to some degree since the beginning of our dataset; a person exonerated in 1973 would have spent a maximum of 10 years on death row, while a person exonerated today could have spent over 50 years. However, one would expect that with a functioning legal system that properly identifies wrongful convictions, the number would plateau regardless of the maximum time spent on death row. For example, if the appeals process consistently identified wrongful convictions within 15 years, the average time on death row would increase until the late 1970s, at which point the data would show a relatively stable horizontal line around the 15-year mark through today. Instead, the average length of time has skyrocketed, especially since the early 2000s. As the years pass, people continue to be exonerated who were sentenced to death at the very beginning of the modern death penalty era. Last year, Oklahoma released Glynn Simmons, who was convicted and sentenced to death in 1975. He endured more than 48 years of appeals in which courts ignored and turned away his pleas of innocence. 

Though the development of DNA testing has greatly assisted in the identification of decades-old wrongful convictions, the availability of DNA evidence does not appear to significantly affect the trend. Only one-sixth of death row exonerations involved DNA. Many capital convictions did not rely on any physical forensic evidence, and when evidence was collected that could be tested for DNA, it may have been improperly stored, contaminated, or lost under the state’s care. Further, many prisoners have difficulty accessing crime scene evidence over the objections of prosecutors so they can test it for DNA in post-conviction proceedings. The distribution of DNA exonerations in our analysis tracks the overall distribution of exonerations, with trendlines showing only a marginal difference—and importantly, the vast majority of the longest-serving exonerated cases did not involve DNA. “DNA is not the answer,” said Ray Krone, a DNA death row exoneree and co-founder of Witness to Innocence, upon Mr. Roberts becoming the 200^th exoneree. Mr. Krone said that DNA exonerations “are like a canary in a coal mine, alerting us to the harder to prove factors that cause most wrongful capital convictions.” 

One likely explanation for the trend involves longstanding efforts to restrict the number and scope of appeals, beginning with the Anti-Terrorism and Effective Death Penalty Act (AEDPA) in 1996. Death-sentenced prisoners are guaranteed direct appeals—one review by the highest state court and then a discretionary appeal to the United States Supreme Court—but these appeals are limited to the facts and evidence that were introduced at trial. Only after this direct review, in state “post-conviction” appeals, can prisoners present new evidence and claims such as ineffective assistance of trial counsel, suppression of evidence by prosecutors, or new DNA results establishing innocence. However, AEDPA imposed a strict one-year deadline for federal post-conviction appeals, and narrowed the grounds upon which federal courts could grant post-conviction relief. Absent extraordinary circumstances, AEDPA also bars death-sentenced prisoners from bringing more than one federal post-conviction appeal. In recent years, Supreme Court decisions interpreting the provisions of AEDPA have further narrowed the legal avenues available to prisoners. 

One problem is that many of the core causes of wrongful convictions, such as official misconduct, false witness testimony, improper forensic evidence or “junk” science, and inadequate legal representation, can often only be brought as claims in state post-conviction appeals, and evidence to support those claims is sometimes slow to emerge by no fault of the prisoner. First, there is no federal constitutional right to counsel in state post-conviction proceedings, forcing prisoners to rely on pro bono lawyers or whatever counsel the state may choose to provide (or not)—and they generally have no legal remedy for the ineffective performance of counsel during these state proceedings. Strict state procedural laws also require that all meritorious claims must be first presented to state courts or they are waived forever.   

Second, capital cases often have many thousands of pages of records and dozens of witnesses with potentially valuable insights in the case—but state statutes of limitations and the one-year deadline imposed by AEDPA, along with chronic underfunding of defense counsel, mean that claims that must be made at this stage are too often missed. If claims are belatedly discovered, prisoners must overcome a mountain of procedural hurdles just to convince a court to consider the merits of the evidence. As a consequence, many prisoners with credible innocence claims are effectively boxed out of court due to draconian procedural rules. In Barred: Why the Innocent Can’t Get Out of Prison, law professor Daniel Medwed writes that “the rule regime is stacked against the innocent, contrary to the popular belief that the postconviction process is full of escape hatches from the prison cell, those imaginary ‘technicalities’ that let people loose.” Prisoners “can have evidence of innocence—and no one willing to hear it.”  

The declining number of death sentences overall may also play a role in the trend. In the 1990s, nearly 300 people were sentenced to death each year, compared with fewer than 50 per year since 2015. Since 2017, every death row exoneration has involved a sentence that is at least ten years old. 

Additionally, the causes of wrongful conviction offer insight into the increasing length of time before exoneration. Most wrongful convictions are caused by more than one reason—a serious indictment of the legal system. The chart below illustrates relationships between different reasons for exoneration and the prevalence of each reason in the overall data. 

Our analysis finds that the role of official misconduct in wrongful convictions cannot be overstated. Prosecutors and police conduct the initial investigation and maintain control over the evidence, including DNA, used to convict and sentence someone to death. When they withhold exculpatory evidence, there is virtually no way for the defense to prove their client’s innocence. Some state officials defend even egregious police or prosecutor misconduct and try to block the defense from developing innocence claims, using tactics like refusing access to the evidence for DNA testing—all of which further delays exoneration. We found that 71% of all exonerations involved official misconduct, but the number was 95% (18 of 19) for exonerations that took 30 years or longer. Over half of all exonerations involved both official misconduct and perjury/false accusations. State admissions of wrongdoing appear to carry great weight for courts evaluating innocence claims, but such admissions are the exception rather the rule. 

State officials have enormous power over whether a person can be declared formally exonerated, and by extension whether they can receive state compensation for their wrongful incarceration. By far the most common method of exoneration in our database is a formal dismissal of charges, a decision made either by the prosecutor or by a court, which often defers strongly to the prosecutor’s recommendation. Nearly all the longest-delayed exoneration cases ended in dismissed charges, confirming the prosecutor’s powerful influence over the process and the failure of the other methods, particularly court-based appellate acquittal, to correct these wrongful convictions. Even in the face of compelling evidence of innocence, many death-sentenced prisoners have been forced to plead guilty to lesser charges and forego compensation in order to avoid the prosecutor’s threat of another trial and possible death sentence. 

In a study of wrongful convictions, law professors Jon B. Gould and Richard A. Leo characterize our criminal legal system as “highly prone to error because of structural truth-seeking flaws.” They find that “various state actors (police, prosecutors, judges) remain entrenched in a highly adversarial mind-set in the post-conviction exoneration process” and “no single state actor or organization seems willing to take responsibility declaring innocence or seeking exonerations.” In fact, based on empirical analysis, “police and prosecutors were the largest source of opposition to an exoneration.” The study finds that political concerns may also create barriers to exoneration, for example when former Virginia Governor Doug Wilder had evidence of Earl Washington’s innocence but commuted his death sentence to life in prison instead of pardoning him. Mr. Washington was later fully exonerated. Professors Gould and Leo suggest that publicly elected officials are “concerned about the ensuing uproar if convicted defendants are released when the evidence is ‘merely’ suggestive of innocence,” but the public should “expect greater openness by our justice officials to a defendant’s showing of innocence, even if presented post-trial.” (See the Death Penalty Information Center’s recent report, Lethal Election: How the U.S. Electoral Process Increases the Arbitrariness of the Death Penalty.)

Mr. Simmons, believed to be the longest wrongfully incarcerated exonerated person in the United States, illustrates both the systemic failures of appellate courts to identify innocence and the lasting prejudicial effects of official misconduct. Accused of a convenience store robbery and murder in Oklahoma, he and co-defendant Don Roberts were identified in a lineup by the surviving witness, who had been shot in the head. Four witnesses testified that Mr. Simmons was playing pool in Louisiana during the murder, but he and Mr. Roberts were convicted and sentenced to death based on the surviving witness’s testimony. Twenty years after the conviction, the trial prosecutor admitted that the witness had wanted to think about the identification “overnight” and had described the perpetrator as being much taller and heavier than Mr. Simmons. “Quite candidly, it was one of the few cases I have been involved in that the verdict a week later could easily have been different,” the prosecutor admitted. Despite these admissions, Mr. Simmons’ post-conviction appeals were denied. Then the defense team found police records, never disclosed to the defense, showing that the witness had identified four other men in lineups, and filed a post-conviction petition in 2023. Only then, with the support of the District Attorney, was Mr. Simmons formally exonerated by a court after a half-century of incarceration. But the DA rejected Mr. Roberts’ request to overturn his conviction in June 2024 and he is still seeking formal exoneration. 

John Huffington and Kerry Max Cook are two other recent examples whose exonerations were delayed for years due to prosecutorial misconduct. In Mr. Huffington’s case, District Attorney Joseph Cassilly withheld two federal reports from the defense for over a decade showing that an FBI agent had lied and misrepresented forensic evidence at trial. Instead of disclosing the reports, DA Cassilly said he had “decided to wait a while to see if the defense files any post-conviction motions in the case”—essentially letting Mr. Huffington use up his limited chances for post-conviction appeals. At the same time, DA Cassilly fought Mr. Huffington’s motions to retest the evidence, continued to withhold evidence even after DNA testing excluded Mr. Huffington as a source, and pursued retrial even after a court vacated Mr. Huffington’s sentence in 2013. Mr. Huffington was forced to enter an “Alford plea” in 2017 to avoid a retrial. DA Cassilly was disbarred in 2021 as a consequence of his ethical violations in the case, and Mr. Huffington was fully pardoned in 2023, 41 years after his original sentence. Only then did he get compensation from the state—$2.9 million—for his wrongful conviction.

In Mr. Cook’s case, prosecutors withheld evidence throughout three trials and death sentences, including a secret deal with a “jailhouse snitch,” and oversaw the destruction of a potentially exculpatory human hair that the defense had sought to test for DNA. In June 2024, the Texas Court of Criminal Appeals ruled that Mr. Cook was “actually innocent” and his case had been “marked by bookends of deception” spanning 46 years. Like Mr. Huffington, Mr. Cook had previously been forced to take a plea when prosecutors threatened a new trial. The ruling means Mr. Cook will now be eligible for about $3 million in compensation.

The increasing length of time before exoneration deserves further research and attention, but our analysis confirms the sobering fact that innocent death-sentenced people are inadequately protected in our legal system. Marcellus Williams faces execution by Missouri in September despite multiple DNA tests proving that he did not produce the bloody shoeprints, hair, and murder weapon DNA left at the crime scene. He has argued his innocence across 23 years of appeals. Prosecuting Attorney Wesley Bell supports Mr. Williams’ innocence claim and filed a motion to vacate his conviction, but Attorney General Andrew Bailey tried to block an innocence hearing and force Mr. Williams’ execution. The Missouri Supreme Court recently authorized the hearing to proceed on August 21. A group of death row exonerees held a press conference in Missouri on August 6 to call for Mr. Williams’ exoneration. “The execution of an innocent person is an irreversible travesty that should never be accepted as an inevitable outcome,” said Herman Lindsey, death row exoneree and director of Witness to Innocence. Joseph Amrine, who spent 15 years on Missouri’s death row, said Missouri “has nothing to gain by killing the wrong person.”