The biggest I found is this one, a goblin soldier named Zolak Assaultcruelty, with about 15 people:
After that, this one, whose head is the local goblin crime lord Smunstu Cloutdooms who was really irritating to interrogate because he hangs out in the catacombs, and starts running through a bunch of rooms halfway through the interrogation, and catacombs are really annoying to navigate. It's about 9 people.
Finally there's this one, which I captured because it contains an assassin.
Now, here's the real kicker, Zolak, and the figure who hired the assassin, are both lieutenants of the Smunstu Cloutdooms. In fact, with a lua script to create a graphiz dot file, we get the following (I was hovering over zolak here, but I didn't capture my cursor, Cloutdooms is in the center, yellow is lieutenant, cyan is asset):
When you interrogate, and find a connection between two organizations, the UI will merge them. However, I cannot connect the lieutenants to the kingpin, because only 'reveal schemes and plots' reveals connections, 'who do you work for' does not right now (it's because there wasn't enough time). This is probably why interrogating intelligent undead doesn't do much as they can't really reveal for whom they work just yet.
Also interesting is that the lua script avoids noting down the connections where a dude is dead, because otherwise it'll very easily pull in all crime organizations in the whole world, which is particularly facilitated by assassins for hire (the assassin I found is also a thief-for-hire for two, three other crime orgs in differrent sites, they are somewhat invisibly in the top-left of the graph).
