It's interesting how the Sheriff described Nancy's pacemaker app disconnects from her phone at 2:28 a.m. He said "app" disconnects correct?
To disconnect a pacemaker app (such as Medtronic MyCareLink Heart, Abbott, or similar) from your phone, you should follow the specific unpairing procedures within the app to ensure data syncing stops properly. Because these apps are used for monitoring medical data, they often require deliberate steps to disconnect.
If someone deliberately disconnected her pacemaker app from her phone then someone had to have been accessing her phone to do that. No?