Washington ? The Supreme Court says a lower court should not have overturned the conviction and death sentence of a man who admitted killing a Kansas sheriff.

The high court on Wednesday unanimously overturned the Kansas Supreme Court’s decision to throw out Scott Cheever’s death sentence for the 2005 fatal shooting of Greenwood County Sheriff Matt Samuels.

The Kansas court said Cheever’s rights against self-incrimination were violated by prosecutors who used a court-ordered mental evaluation from a different trial against him.

Cheever’s own expert argued that methamphetamine use had damaged his brain. Justice Sonia Sotomayor said that because Cheever’s side raised the brain damage issue, prosecutors were entitled to use testimony from the mental health expert from the other trial. That expert said Cheever killed because of an anti-social personality, not because of brain damage.