Fitness trackers, such as the Fitbit or the Apple watch, are
becoming increasingly popular. Users typically wear them for 24
hours a day, and rely on them to monitor their activity, diet and
even sleep. These trackers not only have GPS capabilities that can
pinpoint the wearer’s exact location, but they also record
heart rate and count (literally) every step taken by its users.
Suffice to say, these trackers can act as a ‘black box’
of the body’s physical activities.
Interestingly, fitness trackers are being used by law
enforcement agencies for investigative purposes. For example,
in the United States, Tony Aiello was arrested on October 2, 2018,
on suspicion of murdering his 67-year-old step daughter, Karen
Navarra. Navarra was found dead in her San Jose home with
lacerations to her head and neck. Neighborhood cameras captured
Aiello’s vehicle in Navarra’s driveway. The
Fitbit, worn by Navarra, recorded a spike in her heart rate,
followed by a sudden slowing and
