The lawyers for Duane Edward Buck, who was convicted of a 1995 Harris County double murder, petitioned the Texas Board of Pardons and Paroles and Gov. Rick Perry Wednesday to stop the execution, the Austin American-Statesman reported.
Buck, who is black, was among seven death-row inmates who then-Texas Attorney General John Cornyn said in 2000 had been unfairly sentenced to death because of improper racial testimony.
"It is inappropriate to allow race to be considered as a factor in our criminal justice system," Cornyn, now a U.S. senator, said at the time.
Six of the inmates later received new sentencing hearings but Buck, who is scheduled to be executed Sept. 15, did not.
Cornyn said the seven cases had been tainted by the testimony of psychologist Walter Quijano, who repeatedly told juries defendants were more likely to commit future crimes because they were black or Hispanic. The American-Statesman said his testimony was meant to inform jurors in death-penalty cases on whether a defendant would likely be a future threat to society.
"It's very rare to see an attorney general concede error in a capital case, much less a series of capital cases," said Andrea Keilan, director of the Texas Defender Service, whose lawyers are representing Buck.
"It shouldn't be controversial, and yet no one has stepped forward" to give Buck a new sentencing trial, she said.
The lawyers have also asked Attorney General Greg Abbott and Harris County District Attorney Pat Lykos to agree to cancel the execution date, Keilan said.
"The bottom line is that this guy (Buck) got death based on racist testimony," Keilan said.