'Suspicious' mail with DSA-linked return address triggers FBI, Capitol Hill investigation

What happened: Capitol Hill staff were warned that multiple letters containing suspicious substances were mailed nationwide, including to multiple congressional offices. The FBI, U.S. Postal Inspection Service and U.S. Capitol Police are investigating. Key numbers: Notice issued Thursday. Why it matters: Law enforcement is working to intercept additional letters before delivery, though some may reach their destinations. It is unclear whether the DSA had any involvement. Authorities have not publicly identified the substances or said whether they pose a danger.

Capitol Hill staff were warned that multiple letters containing suspicious substances were mailed nationwide, including to multiple congressional offices. The FBI, U.S. Postal Inspection Service and U.S. Capitol Police are investigating.

Law enforcement is working to intercept additional letters before delivery, though some may reach their destinations. It is unclear whether the DSA had any involvement. Authorities have not publicly identified the substances or said whether they pose a danger.