I sat on a jury a few years ago and the defendants movements were tracked from Worthing to Devon by their mobiles saying "hello" and "goodbye" to various mobile phone masts along the route. Circumstancial of course but with all the other evidence led to a pretty safe conviction.Google or apple know where most people are at most times. The state can access that information if they need it.
That is already a little bit intrusive...
I think you can't be convicted on DNA evidence alone though.