As the hunt intensifies to try to find who sent at least 10 potentially explosive devices to Democrats and critics of President Trump around the country, a second important question lingers: how exactly were the dangerous packages sent?
The FBI and the investigative arm of the U.S. Postal Service, the U.S. Postal Inspection Service, both declined Thursday to confirm to NPR how the packages reached the destinations at which they were intercepted.
But a look at where they were intercepted indicates at least seven of the 10 were handled by the Postal Service. For instance, two of the packages, addressed to Joe Biden, were found in postal facilities in Delaware. The packages addressed to Hillary Clinton and Barack Obama were intercepted in Secret Service mail screening centers.
The delivery methods are still unclear for the packages addressed to Robert De Niro and CNN, which were both received in Manhattan, and the package addressed to and received at George Soros' home, in Westchester County, N.Y.
"I'm not gonna get into where we think the packages came from," said FBI Assistant Director in Charge William Sweeney, boss of the New York Field Office. "Some were delivered through the postal system."
Why would pipe bombs be able to travel any distance at all through the mail?
That answer too remains unclear.
The USPS does have screening processes in place. In a statement, the service said it uses a combination of "specialized technology, screening protocols, and employee training."
But separately, the U.S. Postal Inspection Service website says "the overwhelming volume of mail does not permit the Postal Service to screen every piece."
In terms of spotting the seven packages in question, mail that weighs more than 13 ounces is not supposed to be delivered using just stamps and anonymous drop-off; a person hoping to send such a package is supposed to have to go into a post office and interact with a USPS employee. It's not clear whether the bomb packages weighed more than 13 ounces.
While most of the packages were caught in transit, at least one, to Rep. Debbie Wasserman Schultz, D-Fla., was successfully delivered on Wednesday. The package was originally addressed to former attorney general Eric Holder, but Schultz' office was listed as the return address.
It was delivered there, and her office was evacuated. Schultz said she was "deeply disturbed by the way my name was used."
Anthony May, a former bomb technician for the Bureau of Alcohol, Tobacco, Firearms and Explosives, said the exterior of the packages had obvious red flags that postal workers should be looking out for, including too much postage and misspelled names.
"If it's got excessive stamps on it, the post office is not supposed to deliver that," May said.
Danger in context
While bombs may not usually be sent to such high-profile targets, the USPIS does investigate an average of 16 mail bombs annually.
"By contrast, each year, the Postal Service processed over 170 billion pieces of mail," the USPIS says on a portion of its website dedicated to mail bomb information. "That means during the last few years, the chances that a piece of mail actually contains a bomb average far less than one in 10 billion!"
In fiscal year 2017, the agency opened 19 investigations related to "suspicious substances and items," which includes bombs, explosives and chemical weapons. The agency made 11 arrests and garnered 20 convictions.
There are no indications at this point that the Postal Service plans to make any policy changes in the short or long term related to suspicious packages.
A spokesperson for the American Postal Workers Union told NPR that although much of the media attention this week has been focused on the public figures the packages were addressed to, it's often forgotten that workers are in danger too.
"The reality is, there are a lot of people along the way," the APWU spokesperson said. "They're all certainly at risk here too."
AUDIE CORNISH, HOST:
Ten suspicious packages have been intercepted so far. The packages contained what appeared to be explosive devices and were sent to prominent Democrats and critics of President Trump. The FBI is saying it can't rule out that there may be more suspicious packages moving through the mail now. This story has put the U.S. Postal Service in the spotlight.
Joining us to talk about that is NPR's Miles Parks. He's been looking into postal service policies. Welcome to the studio, Miles.
MILES PARKS, BYLINE: Hi there.
CORNISH: We don't know anything yet about who delivered these packages. What's known so far about how they were delivered?
PARKS: Right. So the FBI and the federal investigation arm for the Postal Service both declined to comment when I asked that exact question earlier today. But we can sort of piece it together based on what we know about where the packages were actually intercepted. At this point, we know that at least seven of the 10 packages were handled by the Postal Service. The packages addressed for Hillary Clinton and Barack Obama, for instance, were flagged in mail screening facilities by the Secret Service, and two of the packages addressed to Joe Biden were also found in postal facilities in Delaware. Obviously that's important because the USPS has screening procedures specifically in place to try to catch incidents and dangerous items like this.
CORNISH: When it comes to mail entering the U.S. postal system, what are those screening procedures?
PARKS: So it's really different based on a number of different factors - you know, the size of the package for instance. But maybe most importantly is who that package is going to. If you want to send mail to the White House or to Capitol Hill or another major federal building, for instance, it's automatically going to go to a separate offsite screening facility to check for suspicious-looking items.
So these suspicious items that we're talking about appear to have been sent using excessive stamps, which is something experts say is one of the first kind of red-flag items to look for during the screening process. At the end of the day, though, the Postal Service does admit that they - that because of the crazy volume that they deal with, they can't screen every single item that enters the system. So they have a system of best practices that they ask companies and even private citizens to use when going through their own mail.
CORNISH: The reports are that these appear to be homemade pipe bombs. It's not clear what kind of damage they could have caused. Can you give us some context. Like, how, I guess, random is this? Like, how often are explosives mailed?
PARKS: Yeah, it's maybe not as rare as one would expect. They - the U.S. Postal Service says it's about 16 - averages out to about 16 bombs per year, which might seem like a lot. But if you consider in the context of more than 150 billion pieces of mail get processed by the postal service every year, it kind of puts it into perspective, specifically when it comes to investigations.
They opened 19 investigations into hazardous material. That could be bombs. That could be chemical weapons that were being - trying to be delivered. It could even be hoax bombs or hoax chemical weapons as well. And they were able to gain 20 convictions in those investigations. But mostly when it comes to the investigations, we're talking about mail theft and mailing of narcotics - is a much higher percentage of what they're looking at.
CORNISH: Are there going to be any policy changes as a result?
PARKS: Not at this point. It doesn't seem that way. Obviously everyone involved in the Postal Service is going to be on much higher alert right now. I talked with somebody at the American Postal Workers Union who made an interesting point basically saying that we've been focused a lot about on the government officials and the media members in the case of CNN who seem to have been targeted by these packages, but there's also postal workers who were put in danger who are carrying these packages point A to point B who are also in danger in these situations. If you remember back to 2001 and the anthrax attacks, there were two postal workers who died back then. So there's no indication that any policies are going to be changed, but we're definitely seeing people on higher alert.
CORNISH: That's NPR's Miles Parks. Thanks so much.
PARKS: Thank you. Transcript provided by NPR, Copyright NPR.