Brian Wharton’s voice cracked as he reached two decades into his memory to describe his role in putting a man he now believed to be innocent on death row.“To those who hold the power to do something here, now is the moment,” Wharton pleaded. “Hear his voice. . . . Listen, and you will hear innocence.”Wharton, the lead detective in death row inmate Robert Roberson’s trial, was testifying before the Texas House Committee on Criminal Jurisprudence on Wednesday, just over 24 hours before Roberson’s scheduled execution.“I’m ashamed that I was so focused on finding an offender and convicting someone that I did not see Robert. I did not hear his voice,” Wharton said to a rapt audience. Donna Farmer, whose son was friends with Roberson growing up,…