No, we are mainly inferring from the arrest warrant application, which gave a time interval of 19:45 to 20:28 for the homicide, that there might be FitBit data that gave this precise time.
Also, know that I saw a LEO on MSM video complain about not finding MT at the "pig farm", because that is the last place her FitBit "pinged". That is my recollection only, an I am not prepared to dig back and find the clip.
LE is not saying much, and the preliminary hearing today was waved, so it may be a while before we hear anymore official info. Maybe the Daily Mail will come up with a jail house bunkie conversation. Who knows, as the folks that do are remaining tight lipped!