More than three dozen members of the US Congress have reported suspicious envelopes containing white powder, prompting office evacuations and a federal investigation ahead of the November 3 midterm elections.
The latest case involved Virginia Democratic Representative Suhas Subramanyam. His district office in Leesburg was evacuated on Monday after an envelope containing an unknown substance arrived.
Subramanyam said staff cleared the office quickly. He condemned the incident and said political intimidation had no place in the country. Initial tests found that the powder was not dangerous, his office said.
Federal investigators are working to identify the people behind the mail campaign. Law enforcement sources told ABC News that more than 100 letters believed to contain white powder were circulating in the US postal system.
The FBI, US Capitol Police and US Postal Inspection Service are investigating the cases. A notice sent to Senate staff on Thursday warned lawmakers’ offices about the suspicious letters.
Election offices in at least 15 states had also reported suspicious mail or threats involving such mail by Thursday evening, according to a report citing federal authorities. Officials have not confirmed the total number of letters, and no suspect has been publicly named.
In a statement, the FBI said it was examining a series of suspicious mailings sent to addresses across the country. The locations included congressional offices, state secretary of state offices and election-related facilities.
Some of the envelopes contained an unknown substance, the agency said. Investigators are working with partner agencies to respond to each report and find those responsible.
The letters have affected lawmakers from both parties. Democratic Senate Minority Leader Chuck Schumer and California Senator Alex Padilla were among those whose letters were intercepted by authorities.
Connecticut Senator Chris Murphy said his team had also received an alert about a letter. The warning came from the FBI, the Senate sergeant at arms and Capitol Police.
Republican senators have reported similar cases. South Dakota Senator Mike Rounds said his Sioux Falls office was evacuated. Nebraska Senator Pete Ricketts and Texas Senator Ted Cruz also reported suspicious mail.
The House of Representatives has faced incidents as well. At least 10 people were exposed after white powder was sent to the offices of New York Democratic Representatives Hakeem Jeffries, Ritchie Torres and Tom Suozzi.
In California, Representative Jimmy Panetta said a staff member opened an envelope at his Santa Cruz office. Staff members then cleared the room and called 911.
Panetta said the incidents would not stop lawmakers from doing their jobs. His comments came as officials across the country dealt with disruptions linked to the suspicious mail.
In Massachusetts, five staff members left the Salem office of Representative Seth Moulton while police examined an envelope. Tests found no substances of concern, according to reports about the incident.
Investigators have identified some common details among the letters. The FBI said recovered envelopes had passed through a mail processing center in north Texas. They also carried a postmark or stamp that read “Thinking of You”.
Senate staff and House offices were told to watch for plain white envelopes with these markings. Most of the suspicious letters were intercepted by postal inspectors and screening facilities before they reached their destinations.
Authorities have not confirmed whether all the reported incidents are connected. They have also not released a final count of the letters or identified a person responsible.
The investigation comes at a sensitive time, with the midterm elections less than three weeks away. Suspicious mail can force public offices to close, lead to safety checks and disrupt work by lawmakers and election officials, even when testing finds no dangerous material.
Similar incidents took place before the 2024 presidential election. Election officials in 17 states were targeted that year, according to previous reports. The person or people responsible for the current cases remain unknown.
Federal agencies continue to trace the letters and examine their contents. Investigators are seeking to determine whether the mailings form part of a coordinated campaign and who sent them.
For now, officials are urging congressional and election offices to remain alert for suspicious envelopes while law enforcement works to protect staff and maintain the security of election operations.

