Defrauding the ATF 

That just seems like a bad idea.

If you’re a police officer in a town of 800 people in Iowa, of course you need a machine gun. That’s just a given. And you’re naturally going to want to have a secondary machine gun too, in addition to your main machine gun. To be safe, you really ought to have a backup for each of those machine guns too. So with a bit of quick math, it’s easy to understand why the 4 person Adair police force needed 16 machine guns.

Still, that leaves them with a surplus of 74 machine guns that’s a little difficult to explain.