A 19-year-old medical student was raped and drowned in the River Dresiam in October 2016. The police identified the accused by a hair found at the scene of the crime. The data recorded by the health app on his phone helped identify his location and recorded his activities throughout the day. A portion of his activity was recorded as “climbing stairs”, which authorities were able to correlate with the time he would have dragged his victim down the river embankment, and then climbed back up.…