Regarding the menezes case - I guess not many of you folk posting here remember the blatant deception in the statements released by the police to back up their claim that they acted with the highest levels of professionalism and dedication and that they 'got their man' - whether this is a deliberate act of concealment or simple stupidity on the part of senior officers who open their big mouths when not in possession of all the facts, is hard to say... the cynic in me says it was damage limitation. 
Some of the statements were worthy of 'ingsoc' and the very worst propaganda fictionalised in 1984.
I also suppose not many of you remember the slavering, vicious thread that popped up on here at the time of menezes' shooting, iirc the title was something like 'We got one!!111!' (of the ********) terrorists etc full of people jumping on the 'facts' (lol, facts indeed...) and loudly and proudly declaring that menezez 'got what he deserved' as a terrorist threat, evil doer, immigrant he deserved to die, was his own fault for doing all the things the police accused him of... only for the true facts to reveal that he did none of the things that the police accuse him of doing to make himself a target. Quite the opposite in fact.
Same goes for tomlinson... the press machine geared up to cast doubt on him as a drunk and a troublemaker who got what he deserved.
...and some of you 'people' (& I use this term loosely) lapped it up like it was ambrosia of the gods 
Accidents happen. And the police are fallible people too. But when there's an error that results in the death of an innocent member of the public then the justice system owes it to the people it is designed to protect to fully and exhaustively pursue the truth... not to allow pathetic obstacles like an expiry of a time limit in which to bring a common assault charge. To do otherwise lowers public confidence in the justice system, every single time and without fail.
To my mind the police are not there to help me... I'm sure that indirectly they contribute to a lower rate of crime in the area that I live, but my personal experience of them has been much below the standard I was brought up to expect from them and to return in my favour. For the most part they have shown themselves to be gung-ho bully boys who have an overweening arrogance when faced with a respectful individual like myself.
As such (and purely from personal experience - not just what I read in the papers about the cases discussed in this thread) I would not trust any of them as far as I can spit. Indeed, I'd have to think very carefully about helping them in 
any instance - It's a sad thing to say. 
 
I just don't trust the police and the courts to act in the interests of integrity and truth; perhaps that's my failing in how I read these cases, but I must add if it was any one of us accused of manslaughter through negligence or overreaction (as in the two cases of menezez and tomlinson), with all the video and witness statements, then we'd not be anticipating a smooth ride at the hands of the cps... an example would have to be made in order to demonstrate the effectiveness of the system - likewise the opposite where the police are concerned as they have to preserve the illusion of respectability and integrity in order that the majority of people retain some respect (I mean fear) of the state and it's agents.
But I begin to digress with opinion and not facts, so I'll conclude with the following:
We don't live in china or north korea or other paragons of fairness and democracy... but that fact should not divert our attention from the need for constant scrutiny and betterment of our law enforcement agencies. Complacency in such a system is 
dangerous.