This issue of a so-called burner phone came up again in the comments by JA at News10. She also claims BG's phone is dead but I don't see how someone could know that just because someone does not respond.You sure can’t! It turns out the SO’s children has the actual smart phone that Brianna had. She gave them it and bought the cheap phone for herself
I wonder if SM and BG had been on a shared plan. BG may have given that phone to SM's older daughter, then BG acquired her own separate burner phone and plan for privacy, maybe some privacy from SM. The primary person on a plan usually has the master ability to read texts, review numbers called, etc., like for children, and the master would likely have been SM?
Burner phone really only means anonymous, no contract. It does not mean prepaid for one month and then throw away, but it could. You can buy service by paying cash and continue to use that physical phone, and you can change your area code and number any time. You can block numbers/texts, too.
JMO BG's last text "I love you" sounded like a good-bye. She could have left and just changed her number or bought a new phone.
SM should be able to provide info about whether BG took anything important with her from her wallet or not, took her phone's charger from the house. All MOO, JMO