Texas poised to execute autistic man for 'shaken baby' death

Barring a successful last-minute appeal, the US state of Texas will execute an autistic man this week whose murder conviction was based on what his lawyers say was a misdiagnosis of "shaken baby syndrome."

Robert Roberson, 57, is scheduled to die by lethal injection at the state penitentiary in Huntsville on Thursday for the February 2002 death of his two-year-old daughter, Nikki.

Roberson's case has drawn the attention of the Innocence Project, which works to reverse wrongful convictions, best-selling American novelist John Grisham, Texas lawmakers and medical experts.

Also among those seeking to halt Roberson's execution is the man who put him behind bars -- Brian Wharton, the former chief detective in the town of Palestine.

"Knowing everything that I know now, I am firmly convinced that Robert is an innocent man," Wharton said at a recent press conference organized by Roberson's supporters. "The system failed Robert."

Grisham, author of the legal thrillers "The Firm" and "A Time to Kill," also appeared at the event and said cases such as Roberson's "keep me awake at night."

"When you get into wrongful convictions, you realize how many innocent people are in prison," said Grisham, a former attorney.

"What's amazing about Robert's case is that there was no crime," added Grisham, a member of the board of the Innocence Project, which has helped free more than 250 innocent people from US prisons since it was founded in 1992.

Roberson's lawyers say the diagnosis of shaken baby syndrome, made at the hospital where his chronically ill daughter died, was erroneous and the cause of death was in fact pneumonia, aggravated when doctors prescribed a wrong medication.

Wharton, the former detective who is now a Methodist minister, said the conclusion by a hospital doctor that the toddler had died after being violently shaken "led the investigation from that point forward, to the exclusion of all other possibilities."

According to his lawyers, Roberson would be the first person executed in the United States based on a conviction of shaken baby syndrome, which the American Academy of Pediatrics now classifies as abusive head trauma.

"In the two decades that have passed since Mr Roberson's trial, evidence-based science has roundly debunked the version of the shaken baby syndrome hypothesis that was put before his jury," said Kate Judson of the Center for Integrity in Forensic Sciences.

The death penalty has been abolished in 23 of the 50 US states, while six others -- Arizona, California, Ohio, Oregon, Pennsylvania and Tennessee -- have moratoriums in place.