As mentioned in a comment above: https://news.ycombinator.com/item?id=33755016

Things like it have happened. The Unabomber was identified through his writing idiosyncrasies.

Lots of criminals have been identified by reanalyzing old DNA samples using data and genealogical techniques that weren't possible at the time the samples were left.

This is the kind of thing that is totally technically plausible, and useful to intelligence groups but not the general public, and therefore I would assume it is 100% in production in international intelligence agencies. But nothing we can "prove" without getting shot.

Similar to ultra-accurate multimedia geolocation models.