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AUSTIN, Texas - The Office of the Attorney General filed a motion for a protective order to prevent Robert Roberson from testifying at the State Capitol on Friday.
According to the attorney general's office, the filing of the motion excuses the Texas Department of Criminal Justice from complying with the subpoena, pending a hearing and resolution of the motion.
"In addition to presenting serious security risks, the subpoena is procedurally defective and therefore invalid as it was issued in violation of the House Rules, the Texas Constitution, and other applicable laws," the attorney general's office said.
RELATED: Death row inmate Robert Roberson subpoenaed to appear before Texas House committee on Friday
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On Dec. 17, Texas lawmakers subpoenaed death row inmate Robert Roberson to testify at the state capitol on Friday, Dec. 20.
The subpoena followed the Texas Supreme Court ruling that while lawmakers cannot block the execution, they can still require testimony beforehand.
Robert Roberson Murder Conviction
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The Backstory: Roberson, 58, was convicted of killing his 2-year-old daughter in Palestine, Texas in 2002.
He took her to the emergency room with a high fever, where medical staff determined her condition was consistent with shaken baby syndrome.
Roberson's attorneys have challenged that diagnosis, calling it "junk science."
They say Nikki died from natural causes, likely undiagnosed pneumonia.
A coalition of lawmakers and the lead detective on the case have argued the science supporting Roberson's death sentence doesn't hold up.
The committee issued a subpoena on the day before Roberson's scheduled execution on Oct. 17 for the death row inmate to testify at a hearing about his case. The Supreme Court paused the execution that night to review the committee's request.
The Supreme Court later ruled that a subpoena could not interrupt a future execution, but said it could compel a witness to testify if no execution was looming.
Some relatives of the 2-year-old have criticized lawmakers for delaying Roberson's execution.
The case has garnered national attention, with hearings including testimony from Dr. Phil and author John Grisham.
The Source: Information from the Office of the Attorney General and previous coverage