Why?
You would think that the other 495,000 people could deal with the baddies themselves. Or at the very least drop a dime on them (or most of them) anonymously, if they chose to do so through fear.
That they don't, speaks volumes for the naivete, or ignorance, of your assumption.
There is no question in my mind that if they are given 12 hours to start delivering the killers and the arms caches, or random bombing begins, they will either deliver them, or verify their complicity.
Are you turning in criminals in your hometown? If not, why not?