WASHINGTON (AP) - The Postal Service takes pictures of every piece of mail processed in the United States, and keeps them on hand for up to a month. Postmaster General Patrick Donahoe says the photos are used mostly for the mail sorting process - but are available for law enforcement, if requested.

WASHINGTON (AP) The Postal Service takes pictures of every piece of mail processed in the United States, and keeps them on hand for up to a month. Postmaster General Patrick Donahoe says the photos are used mostly for the mail sorting process but are available for law enforcement, if requested.

In an interview Thursday with The Associated Press, Donahoe said the photos have been used a couple of times by law enforcement to trace letters in criminal cases, most recently involving ricin-laced letters sent to President Barack Obama and New York Mayor Michael Bloomberg.

Donahoe says the agency's automated tracking program was created after the deadly anthrax attacks in 2001 as a safety measure against hazardous substances.