Justices, in a unanimous ruling handed down Friday, upheld the murder conviction and death sentence of 56-year-old Floyd Maestas.
Maestas was convicted of killing Donna Lou Bott, who suffered more than 30 separate injuries in the 2004 attack.
Among other things, Maestas claimed his defense attorneys should have presented evidence of his low IQ and troubled childhood at trial despite his own objections.
But justices rejected the claim, saying Maestas retained the right to control his own case.
Justices also ruled the defense failed to show Maestas had a significant mental handicap that would exempt him from the death penalty.
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