The U.S. 10th Circuit Court of Appeals in Denver found that Hooks did not receive effective counsel when he was sentenced in Blaine's beating death.
The court said Hooks' attorney failed to thoroughly explore Hicks' background, which included abuse when he was a child and a head injury in an auto accident. The court also said the attorney failed to properly prepare a defense psychiatrist for testimony.
Public Defender Robert Ravitz, whose office represents Hooks, called the agreement appropriate.
Ravitz said Hooks has “severe” brain damage, citing evidence of “significant diminished mental capacity since childhood.”
Hooks apologized in court for killing Blaine, his common-law wife.
“I never meant for this to happen,” he said. “I love her and if I could take her place I would.”