A death row inmate in Texas deserves a new sentencing hearing because his own lawyers called on an expert who claimed he was more likely to be dangerous because he is black, the U. S. Supreme Court has said.

Chief Justice John Roberts wrote the majority opinion in the Feb. 22 decision in Buck v. Davis, saying: "When a jury hears expert testimony that expressly makes a defendant's race directly pertinent on the question of life or death, the impact of that evidence cannot be measured simply by how much air time it received at trial or how many pages it occupies in the record. Some toxins can be deadly in small doses."

The man sentenced to death, Duane Buck, was convicted for two 1995 murders, which included killing his ex-girlfriend in front of her children. He also shot his step-sister at close range.

Buck will now be able to argue before a lower court that he should have a new sentencing hearing.

The 6-2 ruling was dissented from by Justices Clarence Thomas and Samuel Alito.

The case before the Supreme Court did not argue for Buck's innocence, but emphasized his attorneys' handling of the sentencing hearing, which considered whether Buck met the standard for "future dangerousness," CNN reports.

Dr. Walter Quijano, a psychologist retained by Buck's own defense attorneys, spoke at the sentencing hearing and claimed that the fact that Buck was black "increased the probability" he would commit future acts of violence.

Texas law allowed the jury to impose capital punishment only if it found unanimously and beyond a reasonable doubt that Buck was likely to commit acts of violence in the future.

Texas Solicitor General Scott Keller defended the sentence before the high court. He said Quijano's testimony played a limited role at the trial. Other evidence of his future dangerousness cited the brutality of the murders, his lack of remorse, and the testimony of an ex-girlfriend.

During oral arguments, Alito said the race-related testimony was "indefensible" and "bizarre."

Justice Ruth Bader Ginsburg asked "What competent counsel would put that evidence before a jury?"

In the dissenting opinion, Thomas said the lower courts had followed proper standards in upholding the sentence, National Public Radio reports. He added that the jury that sentenced Buck had sufficient reasons to recommend a death sentence on grounds other than Quijano's comments.

Thomas wrote that "Having settled on a desired outcome, the Court bulldozes procedural obstacles and misapplies settled law to justify it."