Texas legislators held a daylong hearing Wednesday examining the evidence and hearing expert testimony in the case of Robert Roberson, the East Texas man who could become the first in the country to be put to death for the disputed “shaken baby syndrome” theory.

The Texas Board of Pardons and Parole’s six members voted unanimously to deny the request. The decision came as lawmakers raised concerns that the courts were not properly implementing a groundbreaking 2013 “junk science” law that was intended to provide justice to people convicted based on scientific evidence that has since changed or been debunked.

The action by the Texas Court of Criminal Appeals comes one day before Texas inmate Robert Roberson is scheduled for execution.