I reviewed some photos of the house, and drove by it this morning. There is a Vivint security sign in the yard.
Why is this important? I'll explain.
I also have Vivint - both security monitoring and home automation. The great thing about automation is that there is a log in the account for entries, exits, alarms, smoke alarms, etc. For example on my set up, I've named each entry point based off its location, and so when an entry or exit happens, it is logged with that name. I also have a doorbell camera that picks up sound and allows for two-way communication. Assuming this homeowner also has a similar setup, and IMO I would expect someone with their supposed education and AirBnB setup to have it - Vivint will have a log of timestamps, even if there was an attempted deletion on the homeowner's end. I imagine this would be a warrant the SLCPD would pursue to corroborate a theory or exonerate a suspect.
Digital footprints are extremely hard to hide - it takes skill and knowledge. IMO, ML was not attempting to hide her tracks, and her information is what will or has lead LE to this point.