Abusing the Material Witness Statute:

'Since the events of September 11th, the government has repeatedly - and some believe, increasingly - imprisoned a number of persons without filing criminal charges against them. The government has detained these persons as material witnesses, arguing that each person is a flight risk and their testimony is necessary for a grand jury's investigation.

The recent, controversial detention of Mike Hawash - a U.S. citizen and Intel engineer - is a case in point. For over five weeks, beginning in mid-March, the United States detained Hawash as a "material witness" because it purportedly wanted him to testify before a grand jury investigating issues related to terrorism. During this time, it never accused Hawash of having committed any act of terror or any crime, or even of being in any way dangerous or a threat. Nonetheless, Hawash was detained under the most severe of prison conditions.

Hawash never testified before the grand jury. Last week, a day before Hawash was due to be released, the government brought criminal charges against him.

Hawash's case raises some very troubling questions: If the government had a basis for criminally charging Hawash all along, why didn't it offer that as the reason for his detention, rather than invoking the material witness statute? Was the reason for detaining Hawash as a material witness so that the government could use the intimidating confinement to obtain information, while avoiding the basic protections that are given criminal defendants? What motivated the government's conduct?

Many observers have been disturbed by detentions like Hawash's, especially because the government has made mistakes. In at least one case, the government obtained a false confession from a material witness who, the government had to later concede before a federal judge, had no terrorist connections.

Some have even suggested that this tactic is unconstitutional, as a Due Process violation or otherwise. In this column, I will argue that the government's tactics are, indeed, unconstitutional, for they violate the Fourth Amendment."
FindLaw's Writ

Looks like the Iraqi's are not the only ones on the target list.

Google: "material witness"