So far, the government has won challenges to the detention of material witnesses.

Detention of material witnesses in criminal cases is permitted.

Federal laws allow material witnesses to be jailed to insure they will appear before a court or a grand jury.

You know what we can do with material witnesses if we want to.

"Master Shelan's name is not on the roll of material witnesses," he pointed out.

Justice Department officials say their detention of material witnesses has been lawful, and critical to the battle against terrorism.

Then, these potential material witnesses were sent off with a bon voyage and a kiss goodbye.

Law enforcement officials have detained some terrorism suspects designated material witnesses for far longer.

The law allows so-called material witnesses to be held long enough to secure their testimony if there is reason to think they will flee.

Even the lawyers who represent material witnesses are often barred from talking about their clients.