Apparently we are discussing two different issues.

You are apparently discussing finding the people involved in this action.

I was discussing actions taken to prevent other terrorist actions in the future.

Yes I agree that if the evidence in this case points to a Muslim Terrorist group that it is fair to expect that most of the people who have information and connections to this case will be Muslims. And in looking for suspects in this case I would look to that community.

However that does not justify a security policy based on racial profiling. It does not justify the assumption that the next terrorist attack will be committed by Muslims.