alt Hacker News> They'd have to fight the feds for jurisdiction and will unfortunately likely lose that fight.
That’s simply not how the system works. There’s no one assigned entity with “jurisdiction” over a crime.
The state and federal governments are dual sovereigns and each are empowered to enforce their own laws. It doesn’t even violate double jeopardy for the Feds and a state to prosecute the same actions.
The only thing that matters is if the state can obtain enough evidence that they feel they could secure a conviction before a jury of the shooter’s peers.
That's simply not how the system works.
The federal sovereign can usurp the state sovereign's courts jurisdiction and use jurisdiction removal[] to try the state charge in federal court. This is exactly what happened when Lon Horiuchi was charged by a state for killing (sniping) an innocent unarmed mother with a baby in her hands, and part of how he got off free.
Given the feds are always keen to do this when possible, it's not for nothing that they do it.
[] https://en.wikipedia.org/wiki/Removal_jurisdiction