Texas legislators held a daylong hearing Wednesday examining the evidence and hearing expert testimony in the case of Robert Roberson, an East Texas man

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 Texas Board of Pardons and Paroles on Wednesday denied a request for clemency for Robert Roberson, who could be the first person in the U.S. executed for a murder conviction tied to the diagnosis of shaken baby syndrome.