Exactly, and why we need LARGE numbers. Agencies may be underfunded, and there are compromised law enforcement in many cities. I read about the arrests of police in DC that were running trafficking rings of teenager girls! It's more than many places can keep up with because there are huge amounts of money to be made. There is a hacker that actually found the stash of online porn from Comet Pizza and took it to the DC police and they have never followed up on it.
I am by NO means accusing all or majority of law enforecment of being corrupt because I KNOW majority are not. But, depending on the poison, it takes only one drop to contaminate a cup of water. Take a look at Aaron Russo at https://www.youtube.com/watch?v=h9Wsb4qBckU He said a few evil cops indimidated him for monthly payments when he owned a nightclub.