— Threat appeared limited to the Senate
October 16, 2026 • 2 min read
Federal authorities are investigating letters with "suspicious substances" that have been mailed to congressional and election offices nationwide and are urging recipients to treat the mailings as "potentially hazardous."
The investigation by the FBI, U.S. Postal Inspection Service, and U.S. Capitol Police was first disclosed in a message from the Senate Sergeant at Arms obtained Thursday by the Associated Press. The notice, sent to Senate offices, said that law enforcement officials were working to intercept any additional letters, but "it is possible that some letters may reach their destinations."
In Congress, the threat appeared limited to the Senate, though the House was monitoring the situation, according to a person familiar with the matter who was not authorized to discuss the investigation publicly.
An FBI statement said the bureau and the Postal Inspection Service were "investigating a series of suspicious mailings sent to various addresses nationwide, including Secretary of State offices and their related election offices."
"Some of the letters contained an unknown substance and we are working closely with our law enforcement partners to respond to each incident," the statement read. "We are also working with our partners to identify the individual or individuals responsible for the letters."
Mailed packages containing a powdery substance led to the evacuation this week of election offices in at least two states, Louisiana and Oklahoma. The Ohio secretary of state said the Postal Service intercepted a package containing a white powder intended for its office and noted that similar mailings had been sent to election officials in multiple states.
News of the letters comes just 3 weeks before Election Day and is reminiscent of a similar threat opens in a new tab or windowin 2023, when election offices in six states received mailings that contained a white powderopens in a new tab or window. In some cases, the incidents disrupted work around local elections.
Some of those letters contained threats and traces of the powerful opioid fentanyl, leading some election offices to stock up on the overdose reversal medication naloxone.
The National Association of Secretaries of State and the National Association of State Election Directors issued a joint statement condemning what they said were threats against election staff.
"Those who administer our elections should never fear for their safety while carrying out their essential duties," they said in their statement.
Deputy Postal Inspector Brendan Donahue told reporters Thursday that "any threat or attack on election officials is unacceptable" and that "we are also working with our partners on identifying the individual or individuals responsible for the letters."