I know that police here in Australia will lie about where a tip came from, including to a Judge -- solely because one of my best friends is a cop and we've discussed it before. The thing is, that could be an isolated incident, I've no idea whether that happens a lot. That said, yesterday there was the article on HN about the Kings County police officer who indeed tried to lie about what had actually transpired, only he was caught out and fired(! Holy crap how good is that). I think none of us have enough info to really know what goes on, so I personally withhold my judgement about it in general, unless in a specific case I have seen credible info to lead me to believe otherwise. Hard topic, tbh.