Jury selection was under way Tuesday in the Dallas capital murder trial of 50-year-old Michael Nadeau when he pleaded guilty to murder, in exchange for a life prison term.
Investigators believe 79-year-old Kathleen White of Irving was strangled during a robbery.
White's body, with an electrical cord around her neck, was located in the trunk of her car at her home. Her dog was found hanged, by an electrical cord, in a shower. Prosecutors believe Nadeau killed the animal to stop the creature from barking during the attack.
Nadeau was arrested in 2010 at an El Paso homeless shelter.