Since the U.S. Supreme Court approved the reinstatement of the death penalty 30 years ago, there has yet to be an instance of DNA proving that an innocent person was executed.


As more cases are re-examined, though, doubt is being cast on a number of executions--especially those in Texas, where the criminal justice system has executed more people than any other state.


The Tribune has been investigating criminal justice issues in depth since 1999. Its examination of flaws in Illinois' death penalty system helped prompt a moratorium on executions in the state.


The paper also has exposed problems in Texas' death penalty system. In 2004, it revealed the faulty science behind the arson investigation that led to the execution of Cameron Todd Willingham. Last year, a Houston Chronicle investigation cast serious doubt on the evidence that sent Ruben Cantu to the death chamber.


The Tribune learned of Carlos De Luna, who was executed in 1989 for a murder in Corpus Christi, after James Liebman, a professor at Columbia Law School in New York City, contacted the newspaper.


Liebman has co-authored studies that found high rates of court reversals due to serious error in capital cases. In subsequent research with students on behalf of the NAACP Legal Defense and Educational Fund, he came across the De Luna case. Liebman asked a private investigator to go to Corpus Christi and look into De Luna's claim during his trial that another man was the real killer.


A woman told the investigator the other man had bragged about committing the murder. Believing De Luna's execution was worth a deeper look, Liebman contacted the Tribune.


"This was no longer a legal or academic enterprise," he said.




From the archives:
Executed on disproved forensics
December 2004: Willingham was convicted of killed his daughters. The evidence has been repudiated.


Under the microscope 
October 17, 2004: A Tribune investigation of forensics shows the questionable science that can sometimes undermine justice.