FBI investigates 'suspicious substances' posted to US election offices

Authorities in the US are investigating letters containing "suspicious substances" that have been posted to congressional and electoral offices.

Recipients have been urged to treat the post as "potentially hazardous" as the FBI, US Postal Inspection Service and US Capitol Police continue their investigation.

The threat first came to light in a message from the Senate Sergeant at Arms, which said authorities were working to intercept any additional letters.

However, the message said, "it is possible that some letters may reach their destinations".

The Senate appeared to be the primary target of the letters, though Congress was monitoring the situation, a source said.

The office of Delaware Democratic Senator Lisa Blunt Rochester said it was sent a letter with a "suspicious substance" that was intercepted by Capitol Police.

California Democratic Senator Alex Padilla said the Postal Service intercepted a suspicious package before it reached his office.

In another incident, Democratic Senator Kirsten Gillibrand said postal inspectors intercepted a suspicious piece of mail addressed to her New York City office.

The FBI 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 bureau said.

"We are also working with our partners to identify the individual or individuals responsible for the letters."

Packages containing an unknown substance led to the evacuation of election offices in at least two states, Louisiana and Oklahoma, this week.

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, the Ohio secretary of state said.

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Numerous states, from Idaho to Florida, said their election offices either received letters or had them intercepted by the Postal Service.

The Wisconsin Elections Commission said it received a letter and tests had shown the white powder enclosed in it was not hazardous.

"Let this be very clear: this incident will not shake us," Wisconsin elections administrator Meagan Wolfe said.

News of the letters comes just three weeks before the midterm and local elections on 3 November and is reminiscent of a similar threat in 2023, when election offices in six states received mailings that contained a white powder.

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 any threats against election staff.

"Those who administer our elections should never fear for their safety while carrying out their essential duties," they said.

(c) Sky News 2026: FBI investigates 'suspicious substances' posted to US election offices