PHOENIX (AP) -- The Arizona Supreme Court has concluded that a man was mentally disabled and cannot be executed for murdering his 2-year-old daughter by dousing her with gasoline and setting her on fire.
The unanimous ruling Wednesday reduces Shawn Ryan Grell's death sentence to natural life in prison.
Grell was convicted of the 1999 murder of Kristen Grell in the desert near Mesa.
The court's ruling says the killing was "horrific" and devastating to the family but that Grell's sentence must be reduced.
The justices say that's because the U.S. Supreme Court has ruled that it would be constitutionally prohibited cruel and unusual punishment to execute someone with mental retardation.
The ruling on Grell says there was more evidence of his mental disability in recent court proceedings than earlier in his case.