Should Jihadi John have been brought to trial?

My opinion is yes, even though thats difficult to do.

Personally Im certainly not concerned at the news of his death, if indeed he is dead. However the relatives of those that were killed in such gruesome ways, appear to have wanted him in court and so thats what should have been done. 

 Also we live in a society where courts and laws built up over many years, are there to decide wether a person is quilty or not. During this process relatives have a chance to hear evidence, that they might not have known, about their loved ones last days and this may help them with closure. This evidence wont be disclosed unless in court. Unfortunately getting in to get him is pretty much impossible.

 If they did hit the wrong person there is no way of telling and they just gave him the best witness protection program, for he will just disappear. The families will now always be left wondering, was it was him or not. If they did hit the wrong person how do we know that person was ISIS or just someone unrelated going about their business. We dont actually have any way of knowing whether they were actually ISIS or not.

Can anyone say without question that Bin Ladin is dead? We saw pictures of someone that looked like Bin Ladin but thats not really proof. DNA would have been better, but we never saw evidence of that, even though they had the body. 

So my opinion is, for the peace of mind of the relatives, he should have been brought to trial even though thats pretty much impossible at present, but with time, who knows. They tracked down Nazi's many years after the deeds were done.