AUSTIN, Texas — Despite a subpoena, which became a key part in temporarily halting his execution, Robert Roberson did not make an appearance at the Texas Capitol on Monday.

The Texas death row inmate was scheduled to be executed last Thursday for the death of his 2-year-old daughter, Nikki, in 2002.

Minutes before he faced lethal injection, the Texas House Criminal Jurisprudence Committee issued a subpoena for him to testify before them, as part of their investigation into the 'junk science' law in his case.

The 2013 law allows a person convicted of a crime to seek relief if the evidence used against them is no longer credible.

"Inviting the death row inmate himself to testify is completely unprecedented," said former prosecutor and Texas attorney, Quentin Brogdon. "Since Mr. Roberson wasconvicted, the sciencehas evolved."

Brogdon added, "Doctors and scientists have since said, 'We'renot as certain as we once thought we were.'"

The bipartisan committee believes Roberson was wrongly convicted based on a faulty diagnosis of shaken baby syndrome.

The committee planned to examine the case during a hearing Monday at the Capitol where Roberson was supposed to appear, but didn't, due to an ongoing dispute over whether he'd appear virtually or in person.

Instead, the committee heard from witnesses who believe Roberson is innocent, including Terry Compton, a juror who convicted him back in 2023.

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Compton testified to the committee Monday, saying she was never made aware during the trial that Roberson's daughter had severe pneumonia and other illnesses that could have caused brain bleeding and bruising.

"Nothing else was ever mentioned or presented to us," said Compton, "I would've found him not guilty."

But, Governor Greg Abbott was not in agreement with the hearing, arguing the committee overstepped its authority by interfering with his power to grant clemency, including execution stays.

In an amicus brief released Monday, Abbott said, "Unless the Court rejects that tactic, it can be repeated in every capital case, effectively rewriting the Constitution to reassign a power given only to the Governor."

Several Republican committee members, including Rep. Jeff Leach, echoed concerns about the separation of powers, but maintained, the subpoena was necessary.

"If we can't speak up and step up and work together to fix the system that has failed Robert and failed Nikki, then what are we even doing?" said Leach.

Committee Chair, Rep. Joe Moody, said the committee's goal was to ensure that Roberson's case is heard, not to instigate a constitutional conflict.

"Each branch is concerned about if we cede power to another branch, that may set a precedent for the future," said Brogdon, "But there are deeper issues involved here."

Roberson's family was at the Capitol on Monday, unsure of whether he would appear in person, or at least virtually.

The committee has said that if Roberson is unable to testify in person at the Capitol, they would go to him at the Polunsky Unit near Livingston, Texas.