Walthers is also charged with trafficking in stolen property, tampering with evidence and theft of a means of transportation.
Police found the body of Worzalla on Feb. 4 after family members reported not hearing from him for more than a week. Officers found signs of trauma to his body, said detective Steve Berry of the Mesa Police.
During their investigation, police discovered that Walthers has been staying in the apartment with Worzalla. She was arrested for vehicle theft when she was seen driving his car, but denied any involvement with his murder.
Berry said first-degree murder charges were added after Walthers' DNA was found on bloody items at the murder scene along with evidence that she had tried to clean up the crime scene.