TEXAS — A Texas man on death row lost one of his last chances to stop his execution set for Thursday. On Tuesday morning, a judge in the county where Robert Roberson was convicted rejected Roberson’s request to cancel his execution because a retired judge allegedly erred.

Roberson was convicted of murdering his ailing 2-year-old daughter more than 20 years ago. He has maintained his innocence and argued his conviction was based on a flawed “shaken baby syndrome” diagnosis. The lead detective in the case, who sided with the state at trial, now says he got it wrong.

“He’s a special man, and I am ashamed that I missed that 20 years ago,” Brian Wharton said outside the courthouse Tuesday morning. “I was, we were, looking for an offender. We labeled him as such, and we made it stick.”

Roberson’s set to be the first person in the U.S. to be executed based on the largely discredited “shaken baby syndrome” hypothesis. 

Prosecutors maintain the evidence is still clear and convincing and that the science around shaken baby syndrome hasn’t changed as much as Roberson’s defense attorneys claim.

Last Friday, the state’s top criminal court refused to stay the Palestine man’s execution. Roberson’s also requested clemency, which is supported by a bipartisan majority of the Texas House. 

“I’ve been doing this long enough to know and to see when the system has failed somebody. And in Robert Roberson’s case, the system has failed at multiple levels. So, the Legislature has a role to step in and to make sure that our justice system is not just preserved, but is strengthened,” Rep. Jeff Leach, R-Plano, said in an interview on Capital Tonight Tuesday. 

The Texas House Criminal Jurisprudence Committee will hold a hearing on Wednesday. 

Click the video above to watch our full interview with Rep. Leach.