WASHINGTON - Lawyers for an inmate whose execution was halted at the last minute urged a Texas court Wednesday to overturn his death penalty on the grounds that it was the result of racial discrimination.

Duane Buck, 49, was condemned to die for the 1995 murder of his girlfriend and one of her friends.

Neither Buck's attorney nor prosecutors dispute his conviction for the double-murder, but they have argued that racial considerations factored into the sentencing phase of his trial.

The Supreme Court intervened just hours before Buck's execution on September 15, 2011, with justices Sonia Sotomayor and Elena Kagan arguing that the case needed to be reviewed because “our criminal justice system should not tolerate (a death sentence) marred by racial overtones.”

Buck's attorneys urged the Texas court in a brief filed Wednesday to vacate Buck's sentence and give him a new trial as a result of the “long history of racial discrimination” in the administration of criminal justice in Harris County, Texas.

“This case is very simple: no death sentence can be supported by an appeal to racial prejudice,” defense attorney Kate Black said.

They cited a study which concluded that from 1992 to 1999 - the period during which Buck was tried and sentenced - prosecutors in Harris County were “over three times more likely to seek the death penalty against African American defendants, than against similarly-situated white defendants.”

The study also found that juries in Harris County were more than twice as likely to impose death sentences on African American defendants than on whites.

The study also found evidence that race played a role in Buck's particular case.

During the 1997 sentencing, psychologist Walter Quijano had testified that Buck was not likely to be dangerous because he had no previous violent record, but said blacks pose a greater risk of “future dangerousness” than whites.

Former Texas attorney general John Cornyn, now a Republican US senator, concluded that there had been an “improper injection of race in the sentencing hearing in Mr Buck's case.”

Cornyn has pushed for new sentencing hearings for seven defendants whose cases had been tainted by Quijano's testimony. Buck is the only one who had not yet received one, his lawyers said.

“Texas should honor the promise that was made by the highest legal officer in the state, then-Attorney General John Cornyn, and grant Mr. Buck a new, fair sentencing not tainted by racial discrimination,” Texas State Senator Rodney Ellis, whose district includes parts of Harris County, said in a statement. - Sapa-AFP