500 detained in 'secret' US anti-terror probe

The US terror investigation that has hauled in hundreds of Middle Easterners is being conducted with closed court hearings and sealed documents on a scale legal experts say may be unprecedented.

As part of what Attorney General John Ashcroft has called the biggest criminal investigation in US history, federal authorities have detained more than 500 people without releasing the paperwork that usually accompanies nearly any type of court proceeding.