A death penalty case long surrounded by questions has been brought to the surface again, with a new report suggesting that the 1989 execution of Carlos DeLuna killed an innocent man. DeLuna's is not the first case to raise such red flags.
DeLuna was convicted of the 1983 stabbing of Wanda Lopez, a convenience store worker in Corpus Christi, Tex. He maintained his innocence while insisting the real killer was Carlos Hernandez, a man who looked much like DeLuna.
According to the report, published by Columbia University law professor James Liebman and colleagues in the journal Human Rights Law Review and online, the similar appearances of the two men may have contributed to mistaken eyewitnesses pinning the crime on DeLuna. Hernandez, who died in prison in 1999, allegedly bragged of the Lopez killing to friends and family.
A sloppy investigation and conflicting eyewitness reports call DeLuna's guilt into question, Liebman wrote in the report. For example, some witnesses reported seeing the killer flee in a disheveled flannel shirt, sporting 10 days' growth of beard and a mustache. DeLuna was wearing a white dress shirt the night of the killing and was clean-shaven. [ History's Most Overlooked Mysteries ]
The report raises new questions about whether Texas executed an innocent man, but it's hardly the first to case to come under scrutiny. Here is a by-no-means-exhaustive list of some of the most controversial cases of the 20th and 21st centuries:
Sacco and Vanzetti: Italian Anarchists (1927)
Death penalty controversy is not a new phenomenon. Italian immigrants Ferdinando Nicola Sacco and Bartolomeo Vanzetti were executed in 1927 after a highly contested series of trials over the shooting death of two men during a 1920 armed robbery. [ The History of Human Aggression ]
Sacco and Vanzetti were followers of Italian anarchist Luigi Galleani, and anti-Italian sentiment almost certainly played a role in their execution, said Michael Radelet, a sociologist at the University of Colorado who specializes in death penalty issues. The accused men waged a then-unprecedented six-year legal battle that went all the way to the Supreme Court twice, and public figures (Albert Einstein among them) called for new trials. But even a confession to the murders by another man, ex-convict Celestino Madeiros, could not save Sacco and Vanzetti's lives. They died in the electric chair on Aug. 23, 1927. Later, several anarchist leaders spoke out to say that Sacco was guilty but Venzetti was not, though historians still debate whether either man really pulled the trigger.
The Scottsboro Boys: Race in Alabama (1931)
Based on the judgment of all-white juries, eight black teenage boys were sentenced to death for the rape of two white women on a freight train in 1931 (a ninth boy, only 12, was judged too young for the electric chair). The trials took place in just a day — with a lynch mob demanding the surrender of the teenagers outside the jail before the trials — and the only lawyers who would defend the accused included a retiree who hadn't tried a case in years and a Tennessee real estate lawyer unfamiliar with Alabama law.
The convictions led to demonstrations in the heavily black neighborhood of Harlem in New York City, and the case eventually made it to the Supreme Court, where the convictions were reversed because of the lack of an adequate defense. Amid enormous public interest, charges were dropped against four of the men. Three were re-sentenced to life in prison; a fourth, Clarence Norris, was re-sentenced to death, later reduced to life in prison. Gov. George Wallace pardoned Norris in 1976. To this day, the Scottsboro case is still shorthand in public dialogue for unfair, racially biased convictions and sentencing.
Bruno Hauptman: The Lindbergh Baby (1932)
The abduction and murder of the 20-month-old son of Charles and Anne Lindbergh was known as "The Crime of the Century" in 1932. Two years later, German immigrant Bruno Hauptmann was arrested after allegedly spending some of the ransom money given by the Lindberghs before they knew that their baby was dead. [ Criminal Minds: A Psychiatrist's View from Inside Prison ]
The crime of the century led to the trial of the century, with Hauptmann maintaining his innocence to the end. Later analyses would call into question much of the evidence that sent Hauptmann to his death, including eyewitness accounts and a lack of Hauptmann's fingerprints at the scene. Books have been written both supporting the 1932 verdict and refuting it, and Hauptmann's widow fought until her death in 1994 to have her dead husband's conviction overturned.
Caryl Chessman: Death Penalty Without Murder (1960)
Californian Caryl Chessman became a flashpoint for anti-death-penalty sentiment in the 1950s. Chessman was convicted of robbery, kidnapping and rape in 1948; the jury determined that Chessman had caused bodily harm during one of the kidnappings, making him eligible for death.
From death row, Chessman wrote books maintaining his innocence and insisting that his original confession had been coerced. There was widespread outrage over the case. Among his supporters, Chessman counted former first lady Eleanor Roosevelt, writer Ray Bradbury and poet Robert Frost.
Chessman missed his chance at a stay of execution (his ninth) on May 2, 1960. As the gas chamber at San Quentin Prison filled with toxic fumes, a legal secretary called to say that a federal judge had issued one more stay of execution. But it was too late for Chessman, who gasped a few times and died.
Teresa Lewis: A Woman on Death Row (2010)
The first woman to die by lethal injection in the state of Virginia, Teresa Lewis was convicted of paying to have her husband and stepson murdered in 2002. Her case drew outcry, because testing had pegged Lewis' IQ at 72, just two points above that classified as intellectually disabled. Lewis' attorneys advised her to plead guilty in hopes of leniency, but she instead received the death penalty. The two hitmen who killed her husband and stepson received life sentences.
Her supporters, among them legal novelist John Grisham, sent thousands of appeals for clemency to Virginia Gov. Bob McDonnell, to no avail. Lewis was executed on Sept. 23, 2010.
Humberto Leal: an International Incident (2011)
The controversy around Humberto Leal's death was not focused on his guilt, but on his legal rights. Leal, a Mexican citizen, was convicted of the 1994 rape, kidnapping and murder of 16-year-old Adria Sauceda, whose body was found bludgeoned on a dirt road in San Antonio, Texas. But police had not informed Leal of his right to call the Mexican consulate upon his arrest, putting the case on shaky grounds.
In 2004, the International Court of Justice in The Hague ruled that Leal and other Mexican nationals on death row had been denied their right to contact their consulate under the Vienna Convention. The Supreme Court in 2008 held that the International Court's judgment was binding, but Congress would have to pass a law to ensure individual states would comply. That never happened.
Citing fears that Leal's execution would harm America's standing in the world, the Obama administration entreated the Supreme Court to stay the execution until Congress could pass the binding law. The Supreme Court concluded that Congress had plenty of time to do so, and denied the appeal. Leal died by lethal injection on July 7, 2011. [ Execution Science: What's the Best Way to Kill a Person? ]
Duane Buck: Racial Bias? (2011)
In a rare move on Sept. 15, 2011, the Supreme Court halted the execution of Texas death row inmate Duane Buck. The stay was a surprise, because the Supreme Court rarely jumps in on death penalty cases unless there is doubt about the defendant's innocence; in this case, the Supreme Court stepped in because of testimony of a psychologist who said black criminals were more likely to commit violence in the future than criminals of other races. (Buck was convicted of killing his ex-girlfriend and her friend in 1995.)
The psychologist's comment led to cries of racial bias, and in 2000, then-Texas Attorney General John Cornyn (now a U.S. senator) recommended that six cases in which the psychologist gave the racially tainted testimony be reopened.
All the cases but Buck's were, and all five of those defendants were re-sentenced to death. The Supreme Court will now decide whether to hear Buck's case. If it doesn't, Buck will have to again appeal to Texas' Board of Pardon and Paroles, which has once before refused to commute his sentence to life in prison. If the board again turns down Buck's request, only Texas Gov. Rick Perry could halt Buck's execution.
Cameron Todd Willingham: Innocent of Arson? (2004)
Of the 243 people put to death during the tenure of Texas Gov. Rick Perry, the case of Cameron Todd Willingham might be the most controversial. Willingham was convicted and executed for the deaths of his three young daughters, who died in a fire at the family's home. Prosecutors alleged that Willingham set the fire and killed the girls to cover up abuse; Willingham's wife, who was not home at the time of the blaze, denied at the time that he abused his children.
The crux of Willingham's case, however, revolved around whether the fire was set on purpose. Central to Willingham's conviction was an analysis by deputy fire marshal Manuel Vasquez concluding that lighter fluid or some other accelerant had been spread throughout the hallways of the home. But in 2004, a second fire investigator, Gerald Hurst, found multiple scientific errors in Vasquez's report and concluded there was no evidence of arson. A 2009 report by the Texas Forensic Science Commission would later come to the same conclusion.
Despite Hurst's criticisms, both the Texas Board of Pardons and Paroles and Perry declined to halt Willingham's execution. He was put to death in 2004.
But that wasn't the end of the Willingham case: In 2009, the case became intertwined with politics after Perry replaced three members of the Texas Forensic Science Commission two days before a meeting on the report, leading critics to accuse the governor of trying to hush up talk of Willingham's potential innocence. When the commission released its report in April 2011, it took no stance on Willingham's guilt or innocence. [ 10 Political Protests That Change the World ]
No matter the strength of the evidence, an admission of fault is unlikely, UC Boulder's Radelet said. There have only been a handful of post-mortem pardons in the U.S., one in 1891 in Illinois and one in January 2011, when then-Colorado Gov. Bill Ritter pardoned a disabled man executed in 1939, Radelet said. With politics at play, he said, there is little motive to look deeply at the Willingham case.
"If Rick Perry ever admitted that Willingham was innocent, his political life would be threatened," Radelet said.
Troy Davis: National Protests (2011)
Amid vigils and protests, Georgia inmate Troy Davis faced the death penalty on Sept. 21, 2011 for the 1989 shooting of a police officer.
Davis' case became a national and international flashpoint because of concerns about witness testimony. Seven of nine eyewitnesses who implicated Davis in the shooting have recanted their testimony, and others say that the man who originally implicated Davis was actually the killer. Public figures as diverse as death penalty opponent former President Jimmy Carter and conservative U.S. representative Bob Barr of Georgia called for reconsideration of Davis' sentence, but on Sept. 20, the Georgia Board of Pardons and Paroles declined to grant him clemency.
In his final statement, Davis maintained his innocence. The case surprised some death penalty experts, including Radelet.
Davis had "a strong case for innocence," Radelet told LIveScience shortly before the execution.
"I have to admit, this one really stumps me," Radelet said. "It really surprises me. I'm just astonished that they're going to let this execution go forward."
: This article was updated at 2:50 p.m. EDT to correct the location of DeLuna's alleged crime.
You can follow senior writer Stephanie Pappas on Twitter . Follow LiveScience for the latest in science news and discoveries on Twitter and on.