WASHINGTON — The FBI, US Postal Inspection Service and Capitol Police are investigating letters “containing suspicious substances” that were mailed to congressional and state election offices, according to officials and notices sent to Hill staff Thursday.
A spokesperson for Sen. Chris Murphy (D-Conn.) confirmed one of the letters arrived at his local office in Hartford.
Packages containing a powdery substance were also opened at election offices in Louisiana and Oklahoma, prompting evacuations. Similar parcels bound for Ohio, Maryland, Mississippi and South Dakota were intercepted by the Postal Service before reaching their recipients, officials in those states revealed.
The FBI, US Postal Inspection Service and Capitol Police are investigating letters containing suspicious substances mailed to congressional offices. FBI
It was not immediately clear which other lawmakers or states were targeted and some letters were intercepted at other addresses.
“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,” a bureau spokesperson said.
“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,” added the rep. “This FBI will continue to safeguard the public and secure elections for American citizens.”
Deputy chief postal inspector Brendan Donahue also confirmed the probe in a press conference Thursday, adding: “Any threat or attack on an election official is unacceptable.”
“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,” read a Senate email notice shared with The Post.
A general view of the United States Capitol Building. Capitol police are probing suspicious letters sent to congressional offices. Christopher Sadowski
The Senate warning included a photo of one of the suspicious envelopes that was postmarked “DSA” and gave a return address at the same Financial District building — 75 Maiden Lane — that the Democratic Socialists of America formerly listed on their membership forms.
“DSA has not occupied this office address since 2013,” a rep for the organization said in a statement. “We are also no longer headquartered at 75 Maiden Lane.”
A Capitol police officer stands outside of the Capitol building in Washington, Tuesday, Aug. 11, 2026. Capitol police are probing suspicious letters sent to congressional offices. Getty Images
It was not immediately clear when DSA moved its operations out of the building.
Congressional offices have been targeted in the past with contaminated letters, most notably in a series of anthrax attacks in 2001 that sent the deadly bacteria causing the disease to Senate offices.
One of those letters arrived at then-Senate Majority Leader Tom Daschle’s (D-SD) office in October of that year, forcing staff to seek treatment while an entire building was later decontaminated.
The mailing spree killed five people and sickened at least 17.
Letters containing ricin, a poison, have also been mailed to Senate offices in the past, but no deaths resulted.