A letter with white powder was opened at Rep. Ritchie Torres' district office in the Bronx on Friday, and six of his staff members were exposed, CBS New York and ABC7 New York reported. After testing, officials determined the powder was not hazardous and no one was injured, CBS New York reported. None of the six showed symptoms, ABC7 reported. The envelope was postmarked from San Antonio, Texas, ABC7 reported, and Torres' team turned it over to the FBI, according to CBS New York. "It was an unnerving experience for everyone on my team," Torres said, according to CBS New York.

The federal investigation has widened to include Republican senators, whose names have not been released, NBC News reported, citing a person with direct knowledge of the investigation. Letters have now reached at least 25 state election offices, including Georgia and Oregon, and at least 10 offices of congressional Democrats, six of them senators, NBC reported. Reps. Maxwell Frost of Florida and Bonnie Watson Coleman of New Jersey also said Friday that their home-state offices got letters, according to NBC. Most if not all of the letters sent to senators were intercepted before delivery, NBC reported. Letters also went to the offices of Senate Minority Leader Chuck Schumer and Sen. Kirsten Gillibrand, both New York Democrats, CBS New York and ABC7 reported.

Earlier Friday, suspicious letters reached the offices of Rep. Seth Moulton and Massachusetts Secretary of the Commonwealth William Galvin, the Boston Globe and Boston 25 News reported. Testing on the powder in Moulton's letter "did not identify any substances of concern," his office said, according to the Globe. In Minnesota, a threatening letter with an "unidentified white powder" addressed to the Secretary of State's office was intercepted Friday, CBS Minnesota reported, citing the office.

In an earlier report Thursday, Votebeat reported that three election officials briefed on the investigation were informed that more than 100 letters were sent. One source described "dozens and dozens" of letters, according to NBC. All of the powder field-tested so far has been found not hazardous, with more lab testing to come, according to a source cited by NBC. Investigators have not traced where the letters came from or who sent them, NBC reported, citing two other sources. The FBI said it is working to identify "the individual or individuals responsible for the letters," according to CBS New York.

What we know: Letters have reached election offices in at least 25 states and targeted lawmakers in both parties, and the powder in a letter opened at Torres' office was not hazardous.
What we don't: Who sent the letters, why, and what final lab tests will show.