FBI investigates "suspicious" letters containing "unknown substance" sent to at least 4 Colorado lawmakers

The FBI is investigating after multiple Colorado politicians were sent letters packed with an unknown white powder, and Colorado isn't the only place targeted.

Similar letters were sent to politicians in more than a dozen other states last week. They were addressed to U.S. senators, representatives and secretaries of state offices.

At least four Democratic Colorado lawmakers reported receiving suspicious letters to their Colorado offices Monday. Luckily, those lawmakers say their staff is safe.

A suspicious letter containing white powder was delivered Monday to Congressman Joe Neguse's Boulder County office.

The Democratic representative shared the following statement:

"I take seriously the safety of my staff and the community I represent, and I'd like to extend my gratitude to the local and federal law enforcement officials who acted swiftly to respond to reports of a threatening letter with suspicious substances being sent to our district office in Boulder County. Because of them, there is no continued threat to public safety in the area.

The nature of this mailing, and others like it being received by elected officials across the country, whether to cause physical harm or provoke unease among public servants, will not prevent me and my team from working day in and day out to serve the people of Colorado's 2nd District.

It's clear that there has been a real, palpable sense of fear percolating in communities across the country lately. And while we know that fear can be contagious, I firmly believe that so is hope. I'll continue to do everything in my power to choose hope — and to stand up for the people of Colorado."

— Congressman Joe Neguse, D-Colorado

The same day, suspicious letters arrived at Congressman Jason Crow's Aurora office and Congresswoman Brittany Pettersen's Lakewood office.

They shared the following statements:

"Earlier today, my congressional office in Aurora received a letter with a suspicious substance. This appears to be one of many unfortunate instances across the country where congressional offices have received mail containing unknown, suspicious substances.

My staff is safe, and our district office remains open for those who need assistance. Attempts to intimidate me or my team will not stop our work on behalf of Coloradans.

I want to thank the FBI, U.S. Capitol Police, Aurora Police Department, and other law enforcement for swiftly working to investigate this matter and keeping everyone safe."

— Congressman Jason Crow, D-Colorado

"This is a deeply disturbing effort to intimidate sitting Members of Congress. I'm grateful for the safety of my staff — who are hardworking public servants, and should not have to fear for their lives while doing their jobs. I'm also grateful to the Colorado FBI for their quick action to protect us. This will be fully investigated and the people responsible must be held accountable."

— Congresswoman Brittany Pettersen, D-Colorado

It's not just Colorado's representatives. Postal investigators intercepted a suspicious letter addressed to Sen. John Hickenlooper's Denver office.

A Hickenlooper spokesperson shared this statement:

"Our office has been notified that postal investigators intercepted a suspicious letter addressed to our Denver office. We're grateful to federal authorities for their work to protect our staff and others who have been targeted. Violence and intimidation have no place in our politics. Not now, not ever."

The FBI and U.S. Postal Inspection Service are investigating the suspicious mailings, which the FBI says are being sent to secretaries of state, congressional and election offices across the country.

While so far only Democratic lawmakers in Colorado have reported receiving the suspicious letters, nationwide, at least three Senate Republicans have received one, as well as several Democratic House and Senate members from other states.

Many of those officials have reported the letters contained white powdery substances, though none have been confirmed to be harmful.

It's not clear what, if anything, the letters said.

CBS Colorado did not find evidence of any hazardous materials response to the reported letters in Colorado, with workers in the shared office buildings of Pettersen's and Hickenlooper's offices telling CBS Colorado they were never evacuated and didn't see any first responders or commotion Monday.

In a statement, the FBI said it's working to identify the person or persons responsible and pledged to safeguard the public and American elections.

"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, and Congressional offices. 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. This FBI and the U.S. Postal Inspection Service will continue to safeguard the public and secure elections for American citizens."

-FBI Denver

Sen. Michael Bennet's Denver office tells CBS Colorado they have not received one of these letters.

CBS Colorado reached out to other state leaders, including Rep. Diana DeGette, Gov. Jared Polis, Secretary of State Jena Griswold, Attorney GeneralPhil Weiser, Rep. Lauren Boebert and Rep. Gabe Evans, and have not heard back about whether their offices received anything suspicious.