An attorney for Robert Roberson III said authorities ignored other possibilities for the 2002 death of the 2-year-old, who’d been ill, and instead accused him of child abuse.

Advocates were fighting for a Texas man’s life on Wednesday just hours before his scheduled execution in the death of his 2-year-old daughter, who prosecutors had argued was killed under the disputed cause known as shaken baby syndrome.

The Texas Board of Pardons and Parole voted Wednesday against supporting clemency for 57-year-old Robert Roberson, who has spent more than 20 years on death row after being found guilty in 2003 of the murder of his daughter Nikki Curtis. Roberson is scheduled to be executed Thursday evening and would be the first person executed in a case involving the cause-of-death ruling, which a number of experts ― including the neurosurgeon who first described the syndrome in a research paper ― say has been misused in the criminal justice system to put innocent people behind bars.

A clemency board document obtained by HuffPost revealed all six parole board members voted against recommending commuting Roberson’s death sentence to a lesser penalty or granting him a 180-day reprieve of his execution. The matter is now in Texas Gov. Greg Abbott’s hands.

Roberson’s lawyers and medical experts who are supporting him are not arguing whether children die of abusive shaking but rather that doctors misdiagnosed Nikki’s injuries. Prosecutors did not consider other causes for her death at trial, and new evidence indicates the girl died of symptoms related to pneumonia, Roberson’s supporters said.

Following the parole board’s recommendation, Roberson’s attorney Gretchen Sween called for Abbott to grant a 30-day reprieve on the execution for a court to hear the “overwhelming” new evidence. She also questioned why a Texas state law allowing prisoners to challenge convictions based on “junk science” hasn’t been invoked to grant Roberson a new trial.

“We pray that Governor Abbott does everything in his power to prevent the tragic, irreversible mistake of executing an innocent man,” she said in a statement.

In the weeks leading up to her death, Nikki had suffered from a respiratory infection, vomiting and diarrhea, according to a motion by Roberson’s attorneys. Roberson, who lived in Palestine, a small town in East Texas, rushed his daughter to the local emergency room on Jan. 28, 2002, and she developed a 104.5 fever the following day.

At the time she was hospitalized, Nikki was prescribed Phenergan, a drug the Food and Drug Administration now restricts for young children because of the risk of breathing difficulties and death, attorneys said in the motion.

Jane Pucher, an attorney on Roberson’s legal team, told HuffPost in an interview on Wednesday that they now know Nikki had both viral and bacterial pneumonia at the time of her hospital visit.

Nikki was discharged, but on the night of Jan. 31, 2002, Roberson was awoken by his daughter crying after falling out of bed, and he comforted her until they both fell asleep, his attorneys said. He later found her unconscious with blue lips and once again rushed her to the emergency room, but her eyes were already fixed and dilated, signs of brain death.

She died on Feb. 1, 2022, after being taken off life support.

Roberson was arrested because detectives said Nikki showed signs of shaken baby syndrome and accused him of child abuse, even though a medical examiner had not yet performed an autopsy. Authorities did not consider other explanations for Nikki’s death or investigate her medical history, his attorneys said.

Pucher told HuffPost that police and medical staff also said he appeared “cold and distant,” which they considered evidence of his guilt. But Roberson was diagnosed with autism, and he was unable to outwardly express his feelings in the moment, which she said were actually “total panic for his child.” The attorney said she thinks his autism “played a really central role in his wrongful conviction.”

Roberson’s case has garnered widespread bipartisan support for clemency, including from 86 Texas lawmakers and scientists.

In 20 days, Robert Roberson will be put to death despite strong evidence of his innocence.

Today, I visited Robert on death row. My colleagues and I are calling for clemency in his case as new evidence and improved science have cast doubt on his conviction.

Roberson has also gained support from Brian Wharton, the former detective who directed he be arrested in 2002 and has since become a Methodist minister. Pucher said Wharton visited Roberson in prison, and Roberson forgave him.

“His ability to do that and to show such graciousness and love for people, no matter how they came into his life. I think that’s just who he is,” Pucher said.

Speaking at a hearing Wednesday before Texas lawmakers, Wharton said he feels shame for his role in Roberson’s conviction, even admitting he had doubts about the case during the trial. He called for Abbott to halt Roberson’s execution.

Abbott, a Republican who supports the death penalty, has used his executive powers to halt an execution only once, in 2018 in the case of Thomas Whitaker, who had been convicted of plotting two murders. That decision happened about an hour before Whitaker was scheduled for lethal injection.

Abbott’s office did not immediately respond to HuffPost’s request for comment.