This is a surprise?
There is a reason men like Thomas Jefferson said government is a necessary evil. Emphasis here on the word evil.
Government exists and operates from a criminal premise--that it is OK to coercively seize private property (money) from individuals against their consent. Think taxes. The opportunities for criminality, corruption, abuse spiral outward from there.
About the most you can say in a situation like the one reported is that the criminals in certain other police departments at least have enough sense to have other cops do the investigating and cover-up clearing.
Always insist on sophisticated criminal overlords, the best available. Never settle for second-rate criminal overlords.