Just found this last night on Microsoft's web page. Microsoft now has a brand spanking new app called Your Phone that lets you sync your phone with your computer. You can see, receive, and send text messages over your computer. It requires the phone to have a wifi connection and for the computer to be connected to the internet. It works through your Microsoft account that you log into your computer with. Then, when you set up, you put the phone number in. It has to be an Android phone to be able to send texts from your computer. This works through the cloud. This came out with the October 2018 Windows 10 Update. SOOOOO...this means that PF could have had someone turn on the cell...who was miles away from him, and then he could have sent text messages to himself and to Doss from the comfort of his own home.
This does not get KK off the hook, because she would have been able to see the text messages on the phone. Also, since this is new, he would have had to know about it, but if he were to google sending text messages from your computer, he would have pulled it up.
This only obstacle would be knowing her password to log into her computer (Microsoft password). However, he knew how to log into her phone, and most people keep some of their passwords written down somewhere.
I installed it on my phone, and it only takes a few steps. Microsoft really guides you through it. I tested it out, and it works. Here is the Microsoft link:
Windows | Official Site for Microsoft Windows 10 Home & Pro OS, laptops, PCs, tablets & more