I heard the same chime on the phone and I am sure LE did too. I imagine any type of last communication Elizabeth Barraza had was checked out.
In today's world of google maps, vehicle navigation systems, and smart phones, would you really have to drive to where Elizaeth Barraza lived in order to find the address of the home? I feel like if I were on Kuykendahl Road, I would know exactly where to turn and how to get to her house just from looking it up on my phone or letting the phone direct me with navigation.
If we assume for a moment that the reason the killer was driving around in the early morning hours of January 25th (12:30 am according to Arrin Stoner video) was not because they were searching for her home address, what other reason could there be?
This criminal must have wanted to get things done and could not wait. If, for example, the killer had gone to the neighborhood a week earlier to look around at the streets and find out where Elizabeth Barraza lived, then waited to commit the crime on the morning of January 25th, 2019, it would have been less likely people remembered surveillance tapes or even kept them. It was going to be rather obvious once the crime happened that police were going to want any surveillance taping from directly before and after the crime.