After Sampson pleaded guilty, a federal jury decided whether he should be sentenced to death or life in prison. The defense introduced mental health experts to testify that Sampson had dyslexia as a child, had bipolar disorder, and "suffered from a significant mental impairment" during the killings. A psychiatrist called by the government testified that Sampson did not suffer from any mitigating mental impairment; he was intelligent but violent and deeply antisocial, with antisocial personality disorder. The jury of 12 unanimously returned a sentence of death.