I read your article you provided the link for. And the man does claim to be an American citizen. I read all the way to the end of the article and found something interesting.
In 1999, a grand jury investigated Shaikh following reports that he may have written prescriptions illegally. He was not indicted.
Maybe they have more evidence now. Perhaps he is being investigated not because he is a Muslim, as you would like us to believe, but because he may be a criminal?
Grand Jury information is confidential and part of that confidentiality is to protect the suspect and the victim. It is not a procedure that should tar the name of any person involved, but it is simply to further the investigation. These gentlemen may have been named by someone else as potential suspects and the security of our nation depends upon checking these things out. Due process does not apply because there was no charge. You obviously do not understand the law very well.
Grand juries also assist in the process of eliminating people who are a part of an investigation wrongly.