>>> weeks after the u.s. government admitted it's been keeping records on phone calls americans make we're now learning about a program at the postal service that does something similar. for decades police have asked the post office to keep track of mail that may involve a suspect in a criminal investigation . now word that all of the mail all of us send and receive is also being duly noted. it being's tom costello has our report.

>> reporter: it was the arrest of shannon guess- richardson that brought the postal service surveillance program out into the program. richardson was arrested charged with sending ricin laced letters to president obama and new york mayor michael bloomberg . richardson 's mail was tracked through a tracking program which photographs and captures an image of every mail piece that is processed, every piece of mail. envelopes from bank and mortgage statements to medical test results to private letters and birthday cards. michael leiter was the director of the national counterterrorism center .

>> this information of where mail is sent and who sent that mail is invaluable to law enforcement professionals. at the same time this information needs to be protected.

>> reporter: in buffalo book store owner lesley james pickering is suing the postal service after a confidential memo showed up in his mailbox revealing his mail was getting more scrutiny. under a freedom of information request he received 33 pages, photocopies of his own envelopes.

>> it's intimidating and it's frightening and i think that's what it's meant to do and what i'm trying to do is not be intimidated and not be frightened and to defense.

>> reporter: he wants political change, even revolution and was once the spokesman for the earth liberation front , a group the fbi labeled as ecrow terrorists. so far the postal service is declining to comment on its mail tracking program but word of its existence comes just weeks after the nsa admitted it's been keeping track of the phone calls americans make and receive.

>> a program that captures all the mail sent by every american to every other american is a very broad and expansive program just to capture a few bad guys.

>> reporter: actually, opening mail requires a court order , but collecting data on what's on every envelope in the system, 160 billion pieces each year, for use in future investigations is now standard procedure. tom costello, nbc news, washington.