Yes, they can if they have reason to think you have broken the law - and they can even read messages that you have deleted if they get a court order and send it to facebook.
The police usually do not have the power to do this. Higher powers like the FBI on the other hand could hack into your accounts, but only if it is serious. I am quite sure you will not be getting hacked anytime soon unless you start breaking some major laws and the FBI or another higher power has to get involved.
Simply stay safe and don't do anything insanely stupid and you should be fine!
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.