By Jonathan Allen and Brad Brooks
(Reuters) -A Texas state judge on Thursday temporarily blocked the execution of a man who had been scheduled to become the first person executed in the United States for murder attributed to shaken baby syndrome, the court said.
Travis County 200th Civil District Court Judge Jessica Mangrum issued the temporary restraining order just hours before Robert Roberson was to be put to death, according to Mangrum's office.
The U.S. Supreme Court earlier on Thursday had denied Roberson's request for a stay of his execution, which had been scheduled to take place at 6 p.m. (7 p.m. ET/2300 GMT).
A spokesperson for the Texas Department of Criminal Justice, which carries out executions, said in an email that the state planned to appeal the restraining order and that the execution could still be carried out on Thursday if a higher court quashes it.
The office of Texas Governor Greg Abbott and the Texas Attorney General's Office did not reply to requests for comment.
Roberson, 56, was convicted of killing his 2-year-old daughter, Nikki, in 2002. The prosecution said he took her to hospital where scans showed she had internal brain trauma of the sort that at the time was thought to indicate a baby had been violently shaken by someone.
In the days before her death, a doctor had diagnosed Nikki as having a viral infection and a fever, and Roberson has long said that on the morning of her death he found she had fallen out of bed.
Many lawmakers in the Republican-controlled Texas House of Representatives have questioned his conviction, and a House committee attempted to buy Roberson time by issuing a subpoena for him to testify before them next week.
The lead detective who helped secure Roberson's conviction has since said he believes Roberson is innocent.
The Texas Board of Pardons and Paroles denied Roberson's bid for clemency on Wednesday.
In a response to Roberson's Supreme Court petition to stay his execution, the Texas Attorney General's Office said Roberson had failed to prove his "actual innocence," and that the Texas Court of Criminal Appeals had ruled that Nikki's injuries were "inconsistent with a short fall from a bed or complications from a virus."
Roberson's lawyers told the Supreme Court that the medical theory used to convict Roberson in 2003 "has since been entirely discredited."
"Not only was abuse presumed in 2003," his lawyers wrote, "but Roberson's blunted affect and aloof mannerisms, manifestations of his Autism Spectrum Disorder mistaken for a lack of care, led medical staff and law enforcement alike to presume culpability."