Supreme Court hears case on 2006 murder conviction

The U.S. Supreme Court will hear arguments on Wednesday regarding the death sentence of Dexter Johnson, a Texas inmate convicted in a 2006 murder. The case tests whether federal courts can accept a second habeas corpus petition when new medical standards change the definition of intellectual disability.

Johnson was found guilty of capital murder for the killing of Maria Aparece, who was 23 at the time. His original execution date was set for May 2019. However, a federal court paused that sentence after legal teams raised a new claim: that Johnson is intellectually disabled.

This argument was not presented during his initial trial. The defense cited the 2013 release of the DSM-5, the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders. That update shifted clinical focus from rigid IQ thresholds to adaptive functioning deficits. Under that new framework, one expert who previously said Johnson did not have a disability withdrew that premise. Two other experts concluded he does meet the criteria.

Ethan Nutter, a lawyer who filed an amicus brief for the National Association of Criminal Defense Lawyers, noted that the medical community’s understanding of the condition has changed over the last 10 to 20 years. He stated that the Supreme Court has previously ruled it is unconstitutional to execute someone who is intellectually disabled.

The Texas Department of Criminal Justice asked the Supreme Court to review the Fifth Circuit Court of Appeals decision in February 2026. The state argued that the lower court’s ruling erases strict limits on claims based on new evidence. The department’s brief also stated that for the families of victims, justice delayed is justice denied.

Protasio Aparece, the father of the murder victim, filed a separate amicus brief. His legal team wrote that Protasio has an interest in seeing justice carried out for his daughter and in preventing other families from suffering decades of excessive delays.

The specific legal question before the justices is procedural. Nutter explained that the court is deciding whether a federal court can address a second or successive habeas petition. A decision in the case is expected by June 2027.