A man convicted of killing three people in three states is challenging the grounds of his death sentence in Oklahoma.
Steven Ray Thacker pleaded guilty in the December 1999 death of Laci Dawn Hill. In a videotaped confession Thacker admitted he kidnapped raped and killed Hill.
Now, Thacker's lawyer claims the state didn't demonstrate the "aggravating circumstances" required for him to be sentenced to die.
Thacker's also been sentenced to die for a murder in Tennessee. He faces life in prison in Missouri.