An envelope containing an unknown white powder was received Monday at the Napa offices of U.S. Rep. Mike Thompson, the latest in a series of suspicious deliveries sent to legislators all over the country.
A staffer for Thompson, D-St. Helena, put the envelope aside after recognizing its return address and stamp from alerts sent out by authorities, according to Lauren Ott, a spokesperson for Thompson.
Other such envelopes have included a threatening note, she said. They have yet to learn what note, if any, was included in Monday’s envelope, she added.
The staffer was wearing protective gear as a precaution and did not open the envelope, which was immediately handed over to police.
U.S. Capitol Police have tested the powder sent to dozens of other congressional leaders and found that it is not hazardous, said Ott. The powder has not been publicly identified.
“I assume it’s to cause fear,” said Ott.
Recently, suspicious envelopes containing white powder have been mailed to Congressional offices across our country. Today, my office received one. My team is trained to handle suspicious mail safely and I am relieved to report no one was hurt. Once my staff member identified the suspicious envelope, he did not open it and he alerted authorities immediately. Thank you to our local law enforcement and first responders who arrived on scene, including Napa County Fire Chief JC Greenberg, City of Napa Fire Chief Zach Curren, HazMat specialists with the Napa Interagency Hazardous Incident Team, and members of the Napa County Sheriff’s Office, Napa County Emergency Medical Services, and CalFire. The case has now been turned over to the FBI. Political violence has no place in our democracy. This attempt to intimidate public servants and our staff will not succeed. Team Thompson will continue to do our jobs and serve the people of California’s Fourth District with pride. — Rep. Mike Thompson (@RepThompson) October 19, 2026
Ott said nothing like this has happened before during her tenure with Thompson’s office. She said U.S. Capitol Police and the FBI are investigating the suspicious envelopes.
In 2001, envelopes containing the bacteria anthrax in white powder form were sent to media outlets and legislators around the country, killing five people and causing illness in 17 others, according to the FBI, which dubbed the attacks “Amerithrax.”