In 1992 Ray Krone was sent to Arizona's death row. A decade, and two separate DNA tests, later Krone left Arizona State Prison at Yuma a free man. What happened to this former Air Force sergeant and postal worker during those 10 years could help change the way the nation pursues capital cases and compensates wrongfully convicted inmates after their release.

Two different juries convicted Krone, now 46, of murdering Phoenix cocktail waitress Kim Ancona. In both cases, the prosecution's case rested largely on matching Krone's dental imprint to bite marks found on Ancona's body.

A 1996 DNA test created doubt regarding Krone's guilt and got him off death row. A subsequent DNA test in 2002 matched crime scene DNA with the actual killer's DNA, freeing Krone and making him the 100th person since 1973 to be cleared of a capital crime in the United States.

The Arizona justice system is beginning to feel the ripple effects of Krone's wrongful conviction. In February, a 30-member Arizona Capital Case Commission recommended nearly two-dozen changes to the state's death penalty system. After analyzing about 230 Arizona death penalty cases from 1974 to July 1, 2000, including Krone's, the commission suggested creating a statewide public defenders office and making minors under 18 ineligible for execution. The state has already enacted the commission's recommendation that mentally retarded defendants be ineligible for the death penalty.

The commission also called for Arizona to place a moratorium on executions, after finding that half of the state's capital cases since 1974 have been reversed. Arizona has executed 22 people since 1992, the year the state re-instituted the death penalty.

Arizona's efforts to revisit its capital cases reflect a larger movement nationwide to address inefficiencies in the death row convictions. Last month, a bipartisan group of congressional lawmakers led by Sen. Patrick Leahy, D-Vt., said they would reintroduce the Innocence Protection Act, aimed at ensuring that fewer defendants are wrongfully convicted. The bill, which passed a Senate committee last year but never was voted on by the full Congress, would give all inmates access to DNA testing after their convictions. It would also push states to set competency standards for defense attorneys in death penalty cases.

Efforts by Congress pushing the Bush Administration to fund post-conviction DNA analysis programs are beginning to bear fruit. The government is proposing to spend $1 billion dollars on DNA analysis over the next five years and another $5 million a year for DNA testing of convicted offenders who may be wrongfully imprisoned.

The Innocence Protection Act would also raise the total amount of damages that may be awarded against the United States in cases of wrongful conviction from $5,000 to $100,000 a year in a capital case.

Last April, Krone was sent home from prison with $50. He's now seeking reparations for the time he spent in jail. He has filed lawsuits against Maricopa County, county officials, the Phoenix Police Department and others, says Chris Plourd, one of Krone's lawyers.

Lawsuits aside, Krone's case has provided an impetus for change. "Eight Arizona death row inmates have been acquitted since 1974, sent home because upon further review jurors didn't believe guilt was established beyond a reasonable doubt," says Assistant Arizona Attorney General Kent Cattani. Krone, however, was the only former inmate to be completely exonerated of his accused crime.

"We've had discussions about what types of conclusions can be drawn from Krone," says Cattani, who also heads the state attorney general's death penalty appeals division. One of the most important lessons learned from the State's case against Krone is that bite mark evidence isn't as compelling as once thought.

"You can tell very limited things from bite marks," says Plourd, a San Diego attorney who took Krone's case prior to the second trial, at the behest of one of Krone's cousins. "A clear bite mark could be useful, but skin is a poor medium for measuring pattern injuries. You cannot make any positive statement with regard to identity."

Steven Drizin, a professor at Northwestern University School of Law in Chicago, agrees. "There are critical lessons to be learned from all wrongful convictions," he says. "(Krone's) case points out the kind of junk that passes for science in the courtroom." In addition to bite marks, Drizin cites hair and fiber evidence as highly unreliable. "Often times, it's the only evidence a prosecutor has, if they don't have a confession or eye witness."

Although DNA testing was available at the time of Krone's original trial, the technology wasn't advanced enough then to dismiss Krone as a suspect. DNA science has evolved over the past decade to provide scientists with a much sharper picture of a person's genetics. Arizona set up a DNA database in 2002, eight years after Krone was sentenced to die. This database would later be the key to matching crime scene DNA with the genetic material of another suspect. Every advance in DNA research brought Krone a step closer to freedom.

Krone was a mailman working in Phoenix at the time of Ancona's murder. Although he was originally from York, a small city in southeastern Pennsylvania, Krone stayed in Phoenix after a seven-year career with the Air Force that ended with sergeant stripes and an honorable discharge in 1981. He knew Ancona prior to the murder, but he maintained his innocence throughout his arrest and subsequent trials.

Krone spent nearly three years on death row. His original conviction was overturned in 1995 when the court determined that prosecutors hadn't given Krone's court-appointed public defender enough time to properly refute damaging testimony from Dr. Raymond Rawson, the State's dental expert.

Plourd joined Krone's defense in 1995 after meeting one of Krone's cousins at an American Academy of Forensic Sciences conference. The cousin has heard of Plourd's work with forensic evidence and convinced the lawyer to meet Krone. "After talking to (Krone), I felt he was innocent," Plourd says. "He was without hesitation willing to do DNA testing to get to the bottom of his case. Usually guilty people don't want to be tested."

During the second trial, Plourd had Ancona's clothing tested for Krone's DNA. Although DNA from saliva found on the clothing did not match Krone's, a jury again convicted him on the strength of Rawson's testimony. This time, however, Maricopa County Superior Court Judge James McDougall found the prosecution's case less compelling and sentenced Krone to life in prison rather than death.

Even after Krone's second conviction for the murder, Plourd felt the pieces still didn't fit together. "One time a prison guard pulled me aside and told me Krone shouldn't be in prison, that he was a 'good guy,'" Plourd says.

Not until 2002 did Krone's defense team have another test done to compare DNA found on the victim with the FBI's national DNA database, which had come online in Arizona a few years earlier. This time, they were able to exclude Krone as the DNA's source. Police were also able to match the crime scene DNA to Kenneth Phillips, 36, a Phoenix man already in prison for an unrelated sex offense. Phillips later admitted the crime, clearing the way for Krone's release.

The Maricopa County prosecutor's office refused to comment on Krone's case because it is in the process of prosecuting Phillips for Ancona's murder and sexual assault, a spokesman says.

"Krone's case was not as unusual as you would have hoped," says Justin Brooks, director of the California Innocence Project. "But it was one of the first cases we've seen where there was an exoneration based on a hit to the DNA database, as opposed to a conviction based on a database hit."

The California Innocence Project operates within California Western School of Law's Institute for Criminal Defense Advocacy. This program lets law students work alongside criminal defense lawyers seeking the release of wrongfully convicted prisoners in California. Krone spoke at the school in March about his experiences in prison and his exoneration.

"He's such a regular guy that got caught up in the system," Brooks says. "When he was first locked up, he believed in the system." Krone's first concerns after being arrested were of missing his next softball game or feeding his dog, he told Brooks.

DNA testing has improved dramatically since Krone's original trial. Krone's was one of the first cases where the court discussed the different ways of testing DNA, including the study of Restriction Fragment Length Polymorphism, Cattani says. RFLP is a technique that scientists us to analyze DNA patterns.

Once Krone was exonerated, the first thing the attorney general's office did was see if any other inmates have been convicted in capital cases on the basis of bite mark testimony, Cattani says. The search turned up the case of Bobby Lee Tankersley, on death row since 1991 for murdering an elderly woman at a Yuma motel. Although Tankersley's case is under review, Cattani says DNA testing in the original case will likely hold up.

Still, Krone's case is responsible for giving Tankersley's appeal another chance. "We look at that type of testimony more carefully now," Cattani says. "People will still use bite mark testimony, but it gives you pause."

Plourd echoes Cattani's concerns. "I'm a strong believer that good scientific evidence is invaluable and bad scientific evidence is harmful to the system."