The former police detective who initially helped to convict Roberson now says he believes investigators succumbed to confirmation bias.
It's not unusual for a death row inmate to claim innocence.
What is highly unusual in the case of Robert Roberson is not only the number of people who believe in his innocence, but who those people are.
Among them: a lead detective who says he bungled the case, dozens of Republican lawmakers who have fought to stop the upcoming execution in Texas, and best-selling author John Grisham, who believes in Roberson's innocence so much that he's writing a nonfiction book about it.
"I'm trying to raise awareness about this incredible injustice and this slowly unfolding trainwreck we're watching right now," Grisham told USA TODAY. "To see something like this is very disturbing."
Roberson, 58, is scheduled to be executed by lethal injection in Texas on Thursday, Oct. 16, for the 2002 death of his 2-year-old daughter, Nikki. Roberson's conviction was based on shaken baby syndrome, which has since largely been debunked as junk science.
If Roberson is executed, Republican state Rep. Jeff Leach said that "it will be an irreparable stain on the history of our state." The Texas Attorney General's Office, which has pushed for an execution date since Roberson won an 11th-hour stay last year, stands behind the decision and says it will be justice served.
What was Robert Roberson convicted of?
Roberson was convicted of killing his daughter, Nikki, in their home in the small East Texas city of Palestine in 2002.
Roberson reported hearing Nikki cry and finding that she had fallen out of bed. After soothing her, he said, they both went back to sleep. Later, when Roberson woke again, he found Nikki wasn't breathing, and her lips had turned blue. At the emergency room, doctors observed symptoms consistent with brain death, and she was pronounced dead the next day.
Doctors and investigators at the time jumped to the conclusion that Nikki died of shaken baby syndrome, even though the toddler also had several grave physical ailments: she had pneumonia in both lungs and undiagnosed sepsis, and she was on prescription opioids that are now banned for children.
A jury convicted Roberson of capital murder and sentenced him to death.
If his execution moves forward, Roberson will be the first inmate in U.S. history to be put to death for a conviction related to shaken baby syndrome.
Lead detective in case: 'We got it wrong'
Brian Wharton, the lead investigator in Roberson's case, told USA TODAY that confirmation bias and several misunderstandings led him to believe that Roberson killed his daughter.
For one, when Roberson brought Nikki to the hospital, nurses, doctors, and investigators observed that he seemed to be devoid of emotion, something Wharton looked at as a red flag at the time but now understands as behavior common among people who are autistic, like Roberson.
Investigators dismissed Wharton's explanation that Nikki had fallen from her bed that night, and Wharton said medical staff didn't divulge the other conditions she had.
"We got it wrong," he said. "We had incomplete and bad information, so the system got it wrong."
Wharton has since apologized to Roberson in person and meets with him monthly on Texas' death row in Livingston, just north of Houston.
"We have conversations about our lives, our faith, our families, and our hopes," Wharton said, adding that Roberson is relying on his faith and is "at peace" with the execution, "but he shouldn't have to be."
"I'm mad as hell that he has to even contemplate such a thing," said Wharton, who has agreed to be among the execution witnesses if it moves forward.
"I will be there for him. I am partially responsible for his being there," Wharton said. "I don't know how I can possibly say no. He's my friend."
Republican lawmakers fight for Roberson: 'This should not be controversial'
Among those who have been fighting for a reprieve for Roberson are conservative lawmakers in the state who are in favor of the death penalty but believe in Roberson's innocence.
Two of them, Reps. Jeff Leach and Lacey Hull, met with Roberson at the prison where he's housed north of Houston on Wednesday, Oct. 8. Leach told USA TODAY afterward that he and Roberson hugged for about 30 seconds and held hands and prayed in a circle with Hull, two Democratic lawmakers, a chaplain, and an assistant warden.
"None of us, not a single one of us, are arguing that Robert should be walking the streets tomorrow," Leach said. "All we're asking for is the pause button and a new trial, but there seems to be this bloodlust for this execution."
The Republican said that legislators receive a lot of requests from death row inmates to review their cases, but Roberson’s stands out among them all.
“It’s not just one thing that was wrong; it’s not just one bit of evidence; it’s not just one witness whose testimony is discredited; it’s literally every stage from the second he brought her to the emergency room to today,” Leach said. “The system has failed him and Nikki virtually at every turn. Total system failure.”
He added: “I’ve never seen anything like it.”
Conservative groups, including Texas Right to Life and Crime Stoppers of Houston, have also come out against Roberson’s execution.
John Grisham: Roberson 'never had a chance'
Grisham, who was a defense attorney before he wrote bestselling legal thrillers like "A Time to Kill," "The Client," and "The Firm," has been following Roberson's case as part of his involvement as a board member of the Innocence Project in New York.
Over the last few years, Grisham has become more vocal about opposing Roberson's execution, including writing op-ed pieces and a nonfiction book set to come out next year depending on what happens with the case.
"If he gets a miracle stay again and somehow gets back into court ... the perfect ending for me would be to see Robert exonerated and walk away," Grisham told USA TODAY.
As part of his research for the book, Grisham has reviewed thousands of pages of court documents spanning decades in Roberson's case.
"He became a suspect right off the bat ... Robert never had a chance at a fair trial," Grisham told USA TODAY. "He was guilty from the very first moment."
Grisham flew to Texas three weeks ago to meet with Roberson and plans to be at the prison if the execution moves forward.
"He's a very sweet person," Grisham said. "My reaction when I left is one of sadness. This poor guy has been here 20 years. Look at what's been taken from him."
State officials stand behind the execution
The Texas Attorney General's Office stands by Roberson's conviction and execution in multiple court filings, arguing that Nikki had other injuries beyond what shaking could have caused, that shaken baby syndrome is not junk science, and that the level of involvement by lawmakers in the case has been inappropriate.
Roberson "brutally murdered his own child," the attorney general's office argued in one court filing. "It can be inferred from the evidence that the night Nikki died, she was crying because her mother was not there. When she would not stop crying, Roberson shook little Nikki to make her stop crying, as he had done many times before."
They cite testimony from two young girls in Roberson's home who they say testified that they had previously seen Roberson shake Nikki.
Roberson's attorney, Gretchen Sween, refutes the state's position as lies and a manipulation of the facts, saying it comes down to politicians wanting to look tough on crime for voters.
"It shouldn't be a matter of who can inflame people; it should be: What does the objective medical evidence say?" she said. "And if you still think you have a case, state of Texas, why not have a new trial? Why are they pushing him to the gurney?"
In a social media thread last year, Texas Attorney General Ken Paxton posted that Rep. Jeff Leach was among those lying about Roberson's case and criticized "eleventh-hour, one-sided extrajudicial stunts" to interfere with Roberson's execution.
"A few legislators have grossly interfered with the justice system by disregarding the separation of powers outlined in the State Constitution," Paxton wrote. "They have created a Constitutional crisis on behalf of a man who beat his two-year-old daughter to death."
What could stop Robert Roberson's execution?
Some appeals are pending in both the Court of Criminal Appeals and the 5th U.S. District Court of Appeals, each of which could rule at any time whether to stop Roberson's execution or allow it to proceed.
Texas Gov. Greg Abbott cannot stop the execution altogether but can grant a 30-day reprieve to give the courts more time to consider the case. His office has not responded to USA TODAY's request for comment.