Newspapers tend to quote Sergeants and above to keep themselves from being sued ( public figures and all). Also, by the time a policeman's Sergeant or above he/she knows enough to NOT say anything politically incorrect to a journalist.
This allows for lies within the system to accidentally feed on themselves... there's no conspiracy here - just a perverse loop of group-think.
Back in a Chicago suburb where I used to live (Du Page) the local “rag” would simply publish a verbatim listing of the blotter. I wasn’t aware of coyness at that level, though little surprises me today even though it does disappoint me.