Ken Paxton is calling on the Texas Supreme Court to overturn the decision delaying Roberson’s execution

Texas Attorney General Ken Paxton filed a petition with the Texas Supreme Court asking the court to overturn its Thursday order delaying the execution of Robert Roberson III. to reject.

The order, issued late Thursday night, hours after Roberson was scheduled to be executed, granted a subpoena from a House committee that called on Roberson on Monday to testify about how the state’s 2013 “junk science” law that enacted it Allowing people to challenge convictions using new scientific findings was applied in his case.

In the 24-page petition filed on behalf of the Texas Department of Criminal Justice, the attorney general’s office says the House committee’s subpoena is “primarily flawed.” Paxton’s motion said the court lacked jurisdiction in the case, and he also said the order “disregards” the separation of powers and brings Texas to the brink of a constitutional crisis.

Related:AG calls on Robert Roberson to testify virtually before Texas House, citing security concerns

During a hearing Thursday afternoon, a Travis County judge halted Roberson’s execution so the death row inmate could comply with the subpoena. The judge signed a temporary restraining order half an hour before his scheduled execution, putting the execution in question.

That order was later rejected by the Texas Court of Criminal Appeals before the Texas Supreme Court stepped in and halted the execution around 9:40 p.m. Thursday.

TDCJ spokespeople did not immediately respond to requests for comment Saturday evening.

Paxton’s petition asked for a decision from the court before noon Monday when Roberson is scheduled to testify, saying Roberson would not appear in person to give his testimony.

Roberson, 57, was convicted of capital murder and sentenced to death in 2003 for the death of his 2-year-old daughter, Nikki. He maintained his innocence for more than two decades on death row.

Part of Roberson’s conviction was based on the theory of “shaken baby syndrome,” which prosecutors used in part to explain Nikki’s fatal injuries. Shaken baby syndrome has been controversial in the years since Roberson’s conviction, but Paxton argues that the theory was not a central factor in Roberson’s conviction.

In 2013, Texas passed a “junk science” law that allowed people convicted of later controversial scientific theories to have their cases reconsidered. Roberson’s execution was originally scheduled for 2016, but was postponed so his case could be reconsidered. However, his appeal failed and his execution was scheduled for Thursday.

The House subpoena came after the House Criminal Justice Committee heard hours of testimony Wednesday from people familiar with the case, including the Anderson County district attorney, Roberson’s attorney and the detective who investigated the case and now believes Roberson is innocent .

In the petition, Paxton argues that shaken baby syndrome was not the core of the state’s case against Roberson. Paxton said in the petition that Nikki was taken to the emergency room with “severe bruising” to multiple parts of her body and that an autopsy showed she died of “blunt force head injuries” rather than tremors.

Gretchen Sween, Roberson’s attorney, argued during her House testimony that the injuries Nikki suffered were due in part to a two-day hospital stay during which a pressure gauge was inserted into her skull to relieve brain bleeding. She said the jury in Roberson’s case was satisfied that Nikki’s status after hospitalization was consistent with the status she had when she was first brought to the hospital.

Roberson claimed Nikki’s injuries were the result of a fall from bed, and Sween testified Wednesday that Nikki suffered from many chronic illnesses, particularly pneumonia, that contributed to her death. In their opinion, no further evidence was presented to the jury.

In the petition, Paxton said evidence at trial suggested Nikki suffered external blows, “not just shaking,” and that the injuries indicated abuse.

“Roberson was sentenced to death in 2003 not for shaking a baby, but for beating his 2-year-old daughter to death,” the petition states.

During Thursday’s hearing in Travis County, Assistant Attorney General Ed Marshall, an attorney with the attorney general’s office, said evidence at trial showed Roberson had a history of “abuse” of his child. Sween said Wednesday that the testimony against Roberson was not credible.

Paxton argues that the Texas Supreme Court lacks “quadruple” jurisdiction in this case. Paxton said the House committee’s efforts to use the judiciary to reverse a decades-old, lawful conviction in a state court violated the separation of powers clause in the Texas Constitution.

Paxton also said the court’s order gave the Legislature power delegated to the executive branch, namely the ability to grant limited reprieves from criminal sentences. On Thursday, many called on Gov. Greg Abbott to grant a 30-day reprieve or commute Roberson’s sentence.

Abbott has not commented publicly on the case. Abbott spokesperson contacted by The Dallas Morning News did not respond to requests for comment Thursday.

Paxton also argues that the subpoena violated Texas House rules requiring subpoenas to be signed by the speaker of the House, which it did not. Paxton also said the subpoena had to be served on a witness named Roberson in the subpoena, while it was instead served on his attorney, Sween.

Paxton also criticized the committee for waiting 21 years after Roberson’s conviction to issue the subpoena, saying Roberson’s conviction was upheld by the Texas Court of Appeals. He also argues that the subpoena subpoenas Roberson but does not require the TDCJ to do anything, nor does it point to the agency that would be required to subpoena Roberson or otherwise make him available to testify.

During Thursday’s hearing in Travis County, Marshall said the case was not a “shaken baby” case and argued that the Court of Criminal Appeals has exclusive jurisdiction.

During the hearing, District Judge Jessica Mangrum asked Marshall whether the legislature’s subpoena for Roberson’s testimony was valid.

“Yes, your honor. As far as I could tell,” Marshall said.

Sween and other representatives for Roberson did not immediately respond to a request for comment Saturday evening. State Reps. Jeff Leach, R-Plano, and Joe Moody, D-El Paso, who are members of the House committee that subpoenaed Roberson, also did not immediately respond to requests for comment Saturday evening.

Staff writer Jamie Landers contributed to this report.