No US governance agency looked at the servers. Only a paid contractor. uS government would need evidence right? The DNC didn't want the government snooping around. So they paid crowdstrike. Why wouldn't they take the free assistance from the US government? The US government angencies have a lot more resources than say crowdstrike...
Interesting to note James Comey was fired the following week.
It was as much on US turf as Hanssen when he received money and dead-dropped secrets. Neither the hackers or Hanssen's handlers were not caught on US turf.