The Texas Defender Service, in an analysis of hundreds of death penalty cases, said that in many appeals, defense attorneys raised no new claims or failed to conduct investigations.
"We're drowning ... in a sea of deficiencies in the death penalty process, and while we're drowning everyone's standing around going 'Everything's fine,'" said Maurie Levin, managing attorney for the service's Austin office.
Texas, the nation's busiest capital punishment state, has executed 232 people since 1982, when the state resumed carrying out death sentences. Over half the executions - 145 - have come under Gov. George W. Bush's more than 5 1/2 years in office.
The Republican presidential nominee, a strong death penalty advocate, has repeatedly rejected criticism of Texas' capital punishment system, contending that no innocent person has been put to death in Texas since he took office in January 1995.
The report, scheduled for release Monday, cited 84 capital cases in which a prosecutor or police "deliberately presented false or misleading testimony ... concealed exculpatory evidence or used notoriously unreliable evidence from a jailhouse snitch."
State Attorney General John Cornyn countered that the state's criminal justice system is working.
"Each death penalty case is reviewed by 12 jurors selected from the community and at least 22 state and federal judges, including the United States Supreme Court," he said. "This system ensures that only the guilty are ultimately convicted and that only the most dangerous criminals representing a continuing threat to society are executed."
An automatic direct appeal applies in Texas for review of any possible trial error plus a second stage of appeals the habeas corpus writ. In it, each death row inmate is entitled to attorneys' fees of up to $25,000 from the state for complete review of evidence.
But in 42 percent of the habeas writs examined, the report said no new investigation was conducted or new claims raised. And in 121 cases, the nonprofit group's attorneys said, prosecutors relied on "junk science" to gain convictions and death sentences.