Federal agents are investigating letters packed with unknown substances and sent to election offices nationwide under a return address long tied to the Democratic Socialists of America, a threat officials call unacceptable.
The FBI, U.S. Postal Inspection Service, and Capitol Police are jointly chasing a series of suspicious mailings that reached congressional offices and Secretary of State election offices across the country. Some envelopes held an unidentified substance. Others were stopped before delivery.
The Post reported that Hill staff received formal notices Thursday as the probe widened. Law enforcement is still working to stop any remaining letters, though officials warned some may still arrive.
An FBI spokesperson laid out the scope in plain terms.
"The FBI and U.S. Postal Inspection Service are investigating a series of suspicious mailings sent to various addresses nationwide, including Secretary of State offices and their related election offices."
The same statement confirmed the core hazard and the manhunt.
"Some of the letters contained an unknown substance and we are working closely with our law enforcement partners to respond to each incident. We are also working with our partners to identify the individual or individuals responsible for the letters."
The bureau closed with a direct pledge: it will keep safeguarding the public and securing elections for American citizens.
One envelope shown to staff carried a clear postmark: “DSA.” The return address listed 75 Maiden Lane in New York’s Financial District. That building once appeared on Democratic Socialists of America membership forms.
A DSA representative moved quickly to create distance. The group said it has not occupied the office at that address since 2013 and is no longer headquartered there. When exactly the organization left remains unclear.
Deputy chief postal inspector Brendan Donahue confirmed the investigation at a press conference Thursday and drew a bright line.
"Any threat or attack on an election official is unacceptable."
Senate staff received an email notice that captured the operational reality. Officials are trying to intercept every remaining letter. They also admitted the obvious risk.
"Law enforcement officials are working to intercept any additional letters before they are delivered, however, it is possible that some letters may reach their destinations."
The targets were not random. Mailings went to congressional offices and to Secretary of State offices that run elections. Which specific lawmakers or states received the letters has not been released. How many envelopes were sent, stopped, or delivered is also unknown. No injuries, exposures, arrests, or office closures have been reported in the current case.
That vacuum of detail does not shrink the stakes. Election offices already face relentless pressure from both legal fights and physical threats. Unknown powder in the mail forces every staffer who opens an envelope to treat it as a potential biohazard until labs say otherwise.
Washington has lived this nightmare before. In 2001 a series of anthrax letters hit Senate offices. One arrived at the office of then-Senate Majority Leader Tom Daschle of South Dakota in October of that year. The mailing spree killed five people and sickened at least 17. The entire building later required decontamination. Staff sought medical treatment.
Separate ricin letters have also reached Senate offices in the years since. Those earlier ricin cases produced no deaths. The pattern is clear enough: powder and toxins mailed to the Capitol remain a recurring tactic against the people who count votes and write laws.
Lab results on the current substance have not been made public. Until those results land, every recipient office must treat the material as dangerous by default. That is the only responsible posture when the powder’s identity is still listed as “unknown.”
Investigators have not named a suspect. No one has claimed responsibility beyond the “DSA” marking on the envelope. The absolute calendar date for the Thursday notices and Donahue’s press conference was not fixed in the initial reporting. The precise number of letters, the full list of targeted states, and any confirmed exposures are still outstanding.
What is already established is enough to demand urgency. Letters carrying an unknown substance were aimed at the offices that administer elections. The return address deliberately evoked a left-wing political organization that says it abandoned that building more than a decade ago. Federal agencies are now racing to stop further deliveries and identify who put the envelopes in the mail.
Threats against election workers are not abstract policy debates. They are concrete attempts to intimidate the people who keep the machinery of self-government running. When powder shows up in those offices, the only acceptable response is a full-speed investigation and zero tolerance for the sender.
