If I remember correctly, didn't the cops suspect him of wearing a bomb vest at the time. Imagine being the police officers in a neighborhood thats never dealt with this type of situation. A gun fight ensues, then several bombs are released, and now the perp who was shooting at you and throwing bombs at you is running towards you. I don't think its hard to imagine that the cops shot at him until he went down. Just like its not hard to imagine that the cops didn't know DVORKAVIK was unarmed while hiding in that boat. Police assume the worse, its for their protection and the protection of the civilians around them. And regarding Tamerlan, does it really matter how he died, the guy set off a bomb at the marathon killing innocent people, hijacked a car, had a gun fight in a friendly neighborhood with police (bullets were flying into near by cars and homes), set off a few pipe bombs in the middle of the street, and your actually concerned with how the police put him down.