I doubt this DNA was combed from the scene three years later. This was a cigarette that was taken three years ago and has been in an evidence locker for years. Finally, today, an arrest is being made. We don't know whether it took three years to do the testing or whether they knew of the match years ago and only now decided to arrest. Three years is a common statute of limitations limit. They could have been working on this from day one and now, with a SOL looming, they have decided to move forwards.
Or maybe the DNA is the announced link and they had an identification by other means. Maybe by relying upon the cigarette they aren't announcing that they have been talking to witnesses/informers. The cigarette is enough to get the warrant, without the need to divulge the existence of informers just yet.
Especially if you haven't mandated DNA tests for Rape Kits and still have a backlog:
Rape, Murder, and Battery are one thing. Protesting and vandalism are quite another.
How many years did the security workers get in jail? In my country that would be quite a few for "intent to cause grievous bodily harm"
https://en.wikipedia.org/wiki/Dakota_Access_Pipeline_protest...
> In September 2016, construction workers bulldozed a section of land the tribe had identified as sacred ground and when protesters entered the area security workers used attack dogs which bit at least six of the protesters and one horse.
>At least six protesters were treated for dog bites, and an estimated 30 were pepper-sprayed before the guards and their dogs left the scene in trucks.
>In May 2017, internal TigerSwan documents leaked to The Intercept and other documents obtained through public records requests revealed a close collaboration between the pipeline company and local, state, and federal law enforcement as they carried out "military-style counterterrorism measures" to suppress the protesters.