Federal officials probe suspicious mail sent to U.S. officials

Envelopes containing suspicious substances sent to congressional offices and election officials. The discovery is triggering a nationwide investigation with the FBI and other federal agencies now working to identify who's behind the letters. Fox News' Tom Fitzgerald live on the Hill tonight. And Fitz, you've been working your sources all day. What are you learning here? Look, the calendar plays a role in this. Today is the 25th anniversary of that first anthrax letter back in 2001 arriving here on Capitol Hill. So you might imagine people are on edge about this kind of thing. Now, so far, officials have not detailed exactly what was in these letters, but they say it was potentially hazardous. So here is what we know. The FBI, the U.S. Postal Inspector's Office and the U.S. Capitol Police all investigating what they describe as letters containing suspicious substances. Now, these were sent to both congressional offices, both here on the Hill and around the country. also election offices around the country. Now, an email obtained by Fox 5 said that this was a white powdery substance and one envelope bore a return address that said DSA with an address in New York City which had previously been connected to the Democratic Socialist America. There is no evidence that there's any connection between that group and this incident. But today, Virginia Congressman James Walkinshaw told Fox 5 he has directed his staff to take precautions. We've had this situation before in our history with white powdery dangerous substances being mailed to congressional offices and others around the country. Obviously, we take every precaution in our office and we'll wait to see the results of the investigation, but it's really disturbing. Now, in a statement to Fox 5, the FBI says they are working to identify the individual or individuals that are responsible for these letters. So how soon could they make a break in this case? Well, the former chief of the U.S. Capitol Police and a former FBI special agent who was assigned to the White House back during those 2001 anthrax attacks tells Fox 5 today these kinds of attacks that come through the mail are difficult cases, but they are not impossible to solve. They're going to do a long history of analyzing both the envelope, the contents, the writing, everything surrounding it. So there's going to be significant research and evaluation done. For a wide array, if you will, of people who do this type of thing for different reasons, the investigation now is going to key in on that. And we're going to also see if anything was put on social media. Late this afternoon, Connecticut Senator Chris Murphy revealed his office received one of those letters. we should know it is less than 20 days right now before the midterm elections. The FBI says they're going to work to secure elections for American citizens. We're live on the Hill tonight. We'll send it back in to you.