[quote=Yog Sothoth]
Well then I meant galactic underworld, and in my opinion if you have empires and civilizations that can cross the galaxy then naturally you would have crime syndicates. Criminals do not follow norms like lawful citizens do so regardless of how isolated you are, there is always the possibility of criminals who will use galactic space travel to make profits
[/quote]

The sheer number of hoops that criminals of one species/civilization would have to jump through to make a profit off of an alien one is mind boggling. It'd be easier to just stick within their comfortable environment.

I mean, criminal enterprise thrives on deniability. Its hard to keep a low profile when you literally look completely different from the guys you're trying to do business with.