MEMPHIS (AP) — The U.S. Supreme Court on Thursday declined to hear the case of a Tennessee death row inmate who claims he should not be executed because he is intellectually disabled.

In a petition filed in January, lawyers for David Keen said tests from 2008 and 2010 prove Keen's intellectual disability. However, there is no procedural mechanism in Tennessee to reopen Keen's case and present the evidence to a court, they argued.

Attorneys for the state opposed Keen's petition. They pointed to a resentencing hearing in 1997 where Keen presented evidence that included a much higher IQ than the later tests.

Keen was sentenced to death for the 1990 rape and murder of 8-year-old Ashley Nicole Reed in Shelby County.

The Supreme Court has previously ruled that executing the intellectually disabled violates the Eighth Amendment's prohibition on cruel and unusual punishment.