I thought and I thought but I can not understand why do people who consider themselves "good muslims" end up murdering innocent people, muslims and non-muslims alike.

I am talking about those responsible for attacks like 9/11. I mean, there might be some justification in blowing up US facilities (even though it is counter-productive), but what justification is given in killings of civilians? Another example being Nigeria blasts.

I know a lot of people disagree with this thinking, but what do you think about people do this? Criminal or Mujahid? Do they have more chances of going to jannat or to dozakh?