FITBIT SCIENCE EXPERIMENT - COMPLETE
Conclusion - Fitbit needs body movement to calculate steps. No physical movement = no steps.
EXPERIMENT:
I have a Fitbit Alta, the same one as MT... I pulled up the Fitbit App on my phone and synced to update my current step count etc. It does not show me any type of location , where I am, or map of where I have been today.
With my Fitbit on my wrist, I walked around and exaggerated my wrist movement and my step count was updating live and continued counting on my Fitbit app, I didn't have to re-sync/update or stop and wait to see how many steps I completed, it was counting live, Started at 1 step and ended at 100 steps.
Next, I took the Fitbit Off of my wrist and put it into a bowl. I walked the same route holding the bowl w/ Fitbit inside and walked, holding the bowl as still as I could, the step count did not change on the App, even though the Fitbit was technically moving around with me. My thought was, possibly Bluetooth/GPS/cell towers could just pick up the movement of the Fitbit from point A to B, not necessarily count by my body movement. BTW, if I moved the bowl just slightly, it counted steps.
LE could take the # of steps on her Fitbit account from a PC and re-create a map, north, south, east, west and go in each direction and see what landmark, forest, house, farm or a field is there. An example would be, 1000 steps recorded the day she disappeared... It would also tell them the time the Fitbit last had activity. If I sit down and watch a 2-hour movie, it will show I had no movement between 2-4 pm on 8/11/18. My last movement was at 2 pm but not 3 or 4 pm. This is also how it tracks your sleep, bedtime and wake time.
LE has to know the day/time MT started moving and stopped and the # of steps from the time she woke up to her last step from that day or days after. If she was sitting on a floor, and bound at the wrists but still twisting her wrist, it would still count steps. It's that sensitive. Also, the App shows the current Fitbit battery life as well.
B
Finally battery life info... If MT has her text messages, incoming calls and alarm clock synced to her Fitbit to vibrate, the battery drains faster. I don't know if this is the case... I will use mine as an example.. Based off 50 text alerts, and 1-2 alarms per day, my Fitbit battery will last 4-5 days. No alarms and a few texts, it will last 7 days +.. I'm sure with everyone in town texting and calling her, trying to locate her, it drained her Fitbit battery fairly quickly and it was drained within 24 hours if she had it synced.