Not a problem with me. Put a trial together. Do it quickly. The family can wait a couple of days until after the dead are burried and a jury can be assembled. Putting that power into the hands of the police is a bad idea. You can execute him rightfully after the trial. Or can't you?
Not in a case of war and this is war. In war, you take out the enemy on the spot without prejudice and justice is well served.
You are thinking in terms of civil rights for a criminal in the US. We just had our first taste of terrorism on 9-11. But the Israelis have been dealing with the behavior and suffering extreme losses of life of innocents for decades. So when they drag a murdering terrorist out onto the street like the dog he his to eliminate him on the spot, then justice has been served johnny on the spot. They tagged the gunman and he received the just reward as the bogus "warrior" doomed for "martyrdom" he was. No need for trial or jury in the case of a war against terrorism when the "martyr" arrives at your door. It's either him or you. If me, then I choose him.