Basically how it works in South Africa. When it comes to murder or justifiable homicide the police are pretty much just there to fill in the paperwork - either stage the scene to make it easier, dump the unregistered weapon you did it with and run or bury the body. A friend of mine popped two random vagrants who wouldn't back the fuck up from him one day with an unregistered weapon and an old lady came out the house and told him to give her the gun and she would cop to it. They didn't even bother trying to prosecute her.

If mainland Europe becomes lawless enough you'll get a booming private security industry like South Africa as well. Generally speaking if you're in trouble anyone with money will call armed response from their security provider and not the police. You don't have to wait half an hour for them to respond.