It's a database of people who are probably not committing crimes either, maybe a few 'crimes of passion' and even fewer 'deranged people', but people who think a little bit don't use these things or can even use them to manipulate investigations.

I do like the twitter post in embedded in the article showing a fit-bit sensing a 119 heartbeat of a raw chicken-filet.

Setting up your fitbit on a chair on a chicken fillet while you're out murdering: "oh no officer I was watching the news, what was on? some tweets of trump or something I dunno..."

"but your heart rate suggest otherwise"

"Okay I was wanking it to bla bla bla, with my left hand, I wank with left, that's why there are no footsteps measured"