Occasionally I notice a lot of data being downloaded without any of my input whatsoever and when I check nethogs, it simply says /usr/bin/python.

Ubuntu updates are not set to download automatically. And there are no other applications that I run which require downloads like this. (Well, there's BOINC, which can access the network only during certain hours, but it's not that either.)

I've noticed this only a few times, so even if there's a reason or pattern to it, I haven't noticed it yet. So, my question is: how I can find out more about what's using the network?