Something along the lines of: okay so you have this guy who's a criminal right? (expand node) here are his phone numbers (expand node) here are the phone numbers who called it (expand node) here are the phone numbers who called those numbers (expand node) here are who they're registered to (expand node) here are their addresses (expand node) here's who else lives there.
I still assume their special sauce isn't their ability to build a node expanding UI, but the data sources they have access to. If they're used for so many government contracts, they're definitely using the data from, say, one police department to inform another. So when another department wants data about criminals, they sign up as a client for the company where that data already is.
And don't discount that the government would pay a huge sum of money to build a surveillance state, even if that surveillance state turned out to be pretty useless.