A bipartisan group of Texas lawmakers have expressed "serious doubts" about the conviction of a killer and are calling for their execution to be halted.

A group of Texas lawmakers, both Democrats and Republicans, urged Governor Abbott and the Board of Pardons and Paroles to halt the execution of a man who was convicted of murdering his two-year-old daughter in 2002.

On Oct. 17, Robert Roberson will be put to death by lethal injection, as prosecutors allege that he killed his daughter, Nikki Curtis, by violently shaking her and causing fatal injuries.

A group of 84 lawmakers from the Texas House, along with medical experts, death penalty attorneys, a former detective on the case, and bestselling novelist John Grisham, have come together to argue that the case against a planned execution was built on faulty scientific evidence in a rare show of bipartisan support in the Lone Star State.

"According to Democrat Rep. Joe Moody, a majority of the Texas House, including members from both parties, have grave concerns about Robert Roberson's execution. Moody emphasized that this issue is about life and death and should not be influenced by political ideology."

The governor of Texas has the power to grant a 30-day reprieve from execution, but full clemency requires the recommendation of the majority of the Board of Pardons and Paroles, which is appointed by the governor.

In his five years in office, Governor Abbott has granted clemency in only one death row case, commuting Thomas Whitaker's death sentence to life in prison an hour before his scheduled execution in 2018. Whitaker had been convicted of arranging a plot that left his mother and brother fatally shot and his father wounded.

The petition of lawmakers claims that Roberson's conviction was based on faulty scientific evidence and highlights that experts have largely discredited the notion that Nikki's symptoms were indicative of shaken baby syndrome.

"Nikki's death was not a crime, but it may be considered a crime if a parent is unable to explain complex medical problems that even trained medical professionals failed to understand at the time," the petition states. "We know that Nikki's lungs were severely infected and straining for oxygen for days or even weeks before her collapse."

In 2002, Roberson, who has always maintained his innocence, took his daughter to the hospital after discovering her unconscious with blue lips. Doctors at the time were skeptical of Roberson's claim that his daughter had fallen off the bed while sleeping, with some testifying at trial that her symptoms were consistent with the signs of shaken baby syndrome.

Medical professionals are increasingly cautioning against diagnosing shaken baby syndrome too quickly, as it can be influenced by a child's medical history.

Those from Stanford University Medical Center, the University of Pennsylvania, and Children's Minnesota Hospital are among the medical experts who signed the petition.

Roberson's lawyers argued that his behavior was misconstrued against him due to his autism, and that physicians neglected to consider other possible medical causes for the child's symptoms, such as pneumonia.

In 2016, the Texas Court of Criminal Appeals put a hold on Roberson's execution. Nevertheless, the court resumed the case in 2020 and set a new date for his execution.

The defense argued that the science of shaken baby syndrome has changed, but prosecutors maintain that the evidence against Roberson remains sound.

A former chief of detectives in Palestine, Texas, who assisted in Roberson's prosecution, publicly endorsed the petition and called for the state to halt the execution.

Wharton stated that he is convinced of Robert's innocence after gaining all the necessary knowledge.

The Associated Press contributed to this report.