the appropriate penalty for terrorist

I am sorry to hear this bad news,extreme Islamist terrorists never stop at nothing, although i am not clear why Islamist terrorists are so horrible, but in Japan's history, Japanese are cruel to treat the other nations in past, most of Aino and Ryukyu in Japan had been assimilated to be Japanese by despotism, so Japan succeeded in becoming a developed and peaceful country. Just it is my opinion,because of civil unrest continues, government should carry out strict despotism to against terrorists,whether killing or executing is well, if i am wrong, whoever will correct me, good luck

Why the children who are the members of tertorists believe killing is right.I don't believe the god of religions taught killing was right.

capital punishment and his body should not be buried in the soil