The man who has confessed to two homicides in a shooting spree throughout 2005 and 2006 is scheduled to testify today against his co-defendant in Maricopa County Superior Court.
Court security has set up a metal detector outside the courtroom in downtown Phoenix, which is expected to be packed, to screen people as they enter.
Dale Hausner has been on trial for three months on 87 charges, eight of which are first-degree murder charges, in connection with the shooting spree that authorities say left eight dead and 17 wounded.
Samuel Dieteman pleaded guilty in April to the killings of Robin Blasnek of Mesa and Claudia Gutierrez Cruz of Scottsdale, both of whom were gunned down on the sidewalk in 2006.
He agreed to testify against Hausner, but he got no deal. The state will still seek the death penalty against him.
The state will also seek the death penalty against Hausner if he is convicted.
Police believe the pair drove around Mesa, Scottsdale, Phoenix and the west Valley and randomly shot people and animals.
Hausner's attorney, Ken Everett, has suggested throughout the trial that Dieteman took Hausner's guns and car and committed the crimes himself.