Texas death row inmate Robert Roberson sat praying in a cell Thursday night, just feet from the execution chamber where he was set to die by lethal injection for the “shaken baby” death of his toddler.

The state’s highest civil court said it wants a lower court to resolve a separation-of-powers issue raised by a group of Texas lawmakers who subpoenaed the death row inmate the night before he was set to be put to death.