This type of interrogations or suspecions should not be given racial tinge or shade as any one especially in security concerns will obviously look with a suspecious mind. Since these poisonous seeds are sown and plants are grown in perticular region or community. I am the first person due to my natural safty instinct will suspect at first look, any person of that region or community.
So it is the responsibility of political leaders of that region or community to reign in such dangerous elements in to their fold. Unfortunately, these (ir)responsible class of people take disadvantage of the situation to promote their own cause. Other innocent people face the brunt of it.
It is also natural that for any ill or good of society, leadership is greatly responsible. If chief of a family does wrong whole family suffers. If a commander errs, all his betallion suffers. If a community leader errs, it brings a bad name to whole community. Is it not a natural law?
In such cases all along the history, a new leadership has emerged. Now it is the time for right people to get their act togethers to marginalise the dangerous elements on war footing.