Updated

People cleared of terror-related crimes, or who have had charges dropped, can still be included on the FBI's terrorist watch list, The New York Times reported Wednesday, citing documents obtained under the Freedom of Information Act.

According to the documents, the FBI can keep someone in the database when it is decided they pose a national security risk -- even if they are not the subject of any ongoing investigation.

"If an individual is acquitted or charges are dismissed for a crime related to terrorism, the individual must still meet the reasonable suspicion standard in order to remain on, or be subsequently nominated to, the terrorist watch list," a December 2010 FBI memorandum says.

The memorandum also informs police officers how to deal with people on the watch list, including directives to never inform the individual they are on the list and to always contact the federal government for further instructions.

Terrorism suspects on the watch list can be kept off planes, blocked from entering the U.S. and subject to greater scrutiny at airports, border crossings and traffic stops. The list now has more than 400,000 names, including about 8,000 Americans, according to statistics released this month, The Times reported.

Ginger McCall, a counsel at the Electronic Privacy Information Center (EPIC), said, "In the United States, you are supposed to be assumed innocent. But on the watch list, you may be assumed guilty, even after the court dismisses your case."

But Timothy Healy, the director of the FBI's Terrorist Screening Center, said it was not feasible for the government to reveal who was on the list because intelligence sources could be revealed.

He said the documents, first obtained by the EPIC and then passed to The Times, showed the government was balancing civil liberties with national security obligations.