GWEN IFILL: And we turn now to a story adding to what was already a tense day on Capitol Hill.
Hari is back with our look.
HARI SREENIVASAN: In Washington and around the country, authorities chased reports of suspicious letters and packages today. At the U.S. Capitol, police briefly evacuated parts of two Senate office buildings, but they offered little information.
OFFICER SHENNELL ANTROBUS, U.S. Capitol Police: Capitol Police is responding to a suspicious envelope. We're currently conducting an investigation.
HARI SREENIVASAN: In all, there were three questionable packages, including one sent to Alabama Republican Richard Shelby. And at the White House, the Secret Service intercepted a letter.
JAY CARNEY, White House Press Secretary: There was a letter sent to, addressed to the president that at an off-site mail facility was noticed to have contained a suspicious substance, and tests were undergone -- undertaken.
HARI SREENIVASAN: New accounts said the letter tested positive initially for ricin, a deadly poison. So did a letter to Mississippi Republican Roger Wicker that surfaced yesterday at a Senate mail facility in Maryland.
But officials cautioned, initial tests are often wrong, and more conclusive testing was in progress. The FBI did say both envelopes were postmarked from Memphis, Tenn. and contained a message that read -- quote -- "To see a wrong and not expose it is to become a silent partner to its continuance." They were signed, "I am K.C. and I approve this message."
Missouri Sen. Claire McCaskill said police have a suspect in mind, but she offered no details. In Phoenix, Ariz., and Saginaw, Mich., investigators examined two more letters sent to local offices of Senators Jeff Flake and Carl Levin. For now, though, the FBI said there is no evidence of a connection between the letters and the Boston bombings.
For more on how the investigation is being viewed on Capitol Hill, we are joined by Todd Zwillich. He's Washington correspondent for "The Takeaway" on Public Radio International and WNYC.
So, Todd, what's the latest that you're hearing from authorities?
TODD ZWILLICH, “The Takeaway”: Well, not much beyond what you just described in the piece, Hari.
I will say it is an odd day on Capitol Hill, between questions coming from the Boston bombing, suspicious packages, letters being delivered by hand to offices, including Sen. Shelby's, a ricin letter towards the White House, and one to the Capitol mail-handling facility out of Washington, D.C.
It has everybody on edge, and, in fact, people in the normal sort of conversations and normal execution of the news around here haven't really had a chance to focus down on one thing. The gun votes are going on, on the floor. People want to know what's the latest with the ricin letters. Does anybody know anything about Boston? Will Boston affect the debate on guns or immigration?
It's been that kind of day, really unusual and a little tense, I'm afraid.
HARI SREENIVASAN: And, Todd, earlier in the piece, we focused on the gun conversation. Some of the family members of the Newtown victims were also in the gallery while all this was happening? Is that right?
TODD ZWILLICH: They were, family members of Newtown victims, also Aurora, Phoenix, from many of the gun tragedies that we have had in this country over the last couple of years.
And many of those families, several of them, I should say, off the Senate floor after the defeat of the Manchin-Toomey gun amendments greeted – Sen. Manchin, Sen. Reid, the majority leader, Sen. Schumer, and other Democrats came and greeted them sort of off to the distance, near the cameras, pledging not to give up. And it was sort of a photo-op, but also a pretty sensitive moment.
HARI SREENIVASAN: So, a lot of folks remember after 9/11 the stretch of time when there were these anthrax letters delivered.
What has Capitol Hill done since then? How has the process changed to try to protect people?
TODD ZWILLICH: Well, you're seeing that in -- with these reports of the letter to Sen. Wicker and also with certain things with Sen. Shelby.
After 9/11 and the anthrax attacks, mail handling on the Hill was moved way off the Hill. There is a mail screening and handling facility in Prince George's County, which is in Maryland, over the District line, far, far away, several miles away from the Capitol.
It was there where the letter containing -- which wound up containing ricin powder was discovered and tested. That facility was shut down. Those mail handlers notified the Capitol Police, who in turn notified the senators and eventually the media. Those are the precautions that were taken after the anthrax attacks.
There was a ricin attack also in 2004 where an envelope was sent to Sen. Bill Frist, at the time the majority leader, also contained ricin powder. You cannot send mail to Capitol Hill now without it being pre-screened, whether that's a package, whether that's a letter.
Everyone who works around here knows that even if you work around here and you just want Best Buy to send your order to work because that's easier, don't do it. It will take weeks because of the screening.
One of the issues with the letter that you described that gave a scare today in Sen. Shelby's office wasn't that -- as I understand it, that the letter itself was suspicious. It's that it was handed off in person. Somebody walked into the office, handed the letter to a receptionist or whoever was at the desk.
That's a violation of protocol because it's not screened. That's why it was suspicious. It gave people and the police pause. It was cleared relatively quickly because there was no suspicious powder or anything else, but it was on this day, these couple of days in tension to hand off a letter in person that gets around the screening process made people step back a bit.
HARI SREENIVASAN: All right, and so what was noticeable today, besides that anxiety that you are describing? How were the staffers that you bumped into all day?
TODD ZWILLICH: I have to say that staffers around here take this kind of thing in stride.
A lot of the staffers around here and a lot of journalists were around for the anthrax attacks, when those letters were opened in offices, when people were quarantined, they were forced or asked to take antibiotics; there were hazmat teams in white and yellow suits running around. This has been nothing like that.
Yes, it makes people a little bit tense, but the removal of mail handling off the Capitol Hill complex and into Maryland I think gives people, at least around here, a measure of security because they know, in this case, that while it is a threat on Sen. Wicker's office in this case, it never got close to them personally. And I think that makes people feel a lot better.
HARI SREENIVASAN: All right, Todd Zwillich from Public Radio International and WNYC, thanks so much.
TODD ZWILLICH: Pleasure, Hari.