Texas executed a man Thursday evening for the 2004 killing of a Texas Christian University professor, marking the state's 600th execution since resuming capital punishment in 1982.

The execution proceeded after the U.S. Supreme Court lifted a stay that had been issued over claims that the condemned man was intellectually disabled. The court's decision was divided, clearing the way for the lethal injection to move forward.

Experts for both the prosecution and defense had assessed the man as intellectually disabled, according to court documents. However, the Supreme Court's action allowed Texas to proceed with the scheduled execution despite these findings.

The case involved the death of a retired college professor from TCU. The killing occurred in 2004, leading to the man's eventual conviction and death sentence.

Texas has carried out more executions than any other state since the Supreme Court allowed states to resume capital punishment in 1976. The state resumed executions in 1982 and has since become the nation's most active in implementing the death penalty.

The execution highlights ongoing legal debates over intellectual disability claims in death penalty cases and the standards used to evaluate such claims in capital punishment proceedings.