I take this to mean that we caught them in these networks and have uprooted and blocked them back out. Otherwise that means they actually executed some kind of attack which would be really stupid for a variety of reasons.
Nope, and nope.
It means we have LOGS that indicate SOMEONE was in these networks from SOMEWHERE else, and they downloaded a lot of files.
Oh, and the network maintenance and security was malfeasant, but close enough for Government work.