JS
The robbery would have backfired if there was something about the way it was carried out that caused the robber to die. But for a man to assassinate a thief after the robbery had been executed is an entirely different thing, and, as Thorne says, the killing is unjustified because it takes place "after the fact" and is caused by something other than a desire to protect life or property. The law is disgraceful.
As for the "felony murder" you describe, I don't have too much of an issue with making an accidental killing during the commission of a crime, murder, but I see that as entirely separate from the situation where a householder kills a burglar to prevent escape. As you say, the death was caused by the crime in the first instance, but it was a separate act that was not caused by the crime in the second. The householder had a choice and chose to take justice into his own hands. He was free to let the police do their jobs and apprehend the thief later.
Your statement that if a car thief dies during the theft, that is neither unfortunate nor a prevention of justice is revealing. I am tempted to cease this discussion immediately, because I doubt there is any point continuing it. I cannot accept that death has any role in a civilised penal system - not even where genocide has been committed, or where the killer is a compulsive serial killer who if let loose will repeat his crimes over and over until he dies of old age. These people should be removed from society, but they need not be killed. So to say that a person's death in a car accident is "justice" because the car was stolen is abhorrent to me. There is nothing "just" about a quirk of fate, however satisfying you might find it to be.
Your argument about the booby-trapped car verges on the ludicrous. To answer your question quite simply, there are many alternative and effective ways of protecting a car from theft, so to make it a death trap is unnecessary to stop it being stolen. You have many other choices, but you choose to use a method that kills indiscriminately. That is deliberate murder, and the pretence that you are protecting your property is fatuous.
Yes I do object to the killing of terrorists by remote jamming in the same way as I would object to ending a hostage situation by tossing in a hand grenade. It is indiscriminate. The chances of success are low. The chances of innocent victims being killed at the same time as the terrorists are high. There is absolutely no connection with the administration of justice, even where the jamming is done to prevent a crime. There are better alternatives.
With reference to your footnote, I suspect the only reason the CPS did not proceed with the prosecution was because it felt it could not secure a guilty verdict, not because it felt Bennell got what he deserved. As for your hope that his example would serve as a deterrent, have you seen the news from Salford tonight? http://www.bbc.co.uk/news/uk-england...ester-14467588