I think if you look at the cite, and the links available, you'll see that it is based upon actual arrest data submitted by law enforcement, excluding instances where people are arrested "on suspicion" of some crime.
So, are the cops lying about the number of arrests? I don't know. I'm sure you believe that. I don't really care. I simply put the cite in my post because cops claim they had at least 11 million interactions with the public, excluding traffic offenses, in 2013, and so I wanted to point out that even if you can give me a bunch of citations per day to some cop somewhere beating up a guy or shooting a guy or whatever, it's still just a tiny, tiny fraction of the overall daily interactions between citizens and law enforcement in this country. Not to say that it's right for a cop to ever act illegally, but contrary to the claim of Priceless and others here, it is still just a rarity.