The package was found at a West Hartford post office on Monday, Sept. 16, the Connecticut Secretary of State said in a news release. No one was injured, but the contents were sent to a lab for testing.
Election offices in New York, Tennessee, Wyoming, Kentucky, Oklahoma, Iowa, Nebraska, Missouri, Kansas, Indiana, Massachusetts, and Colorado received the suspicious packages, according to ABC News.
Similar packages addressed to election offices in Connecticut, Maryland, and Maine were intercepted before they reached their destinations.
It's unclear how many could remain in circulation that investigators have not found. So far, none of the packages have contained any actual harmful materials.
Despite the lack of motive, the mailings could have a chilling effect on poll workers who are afraid for their safety in a contentious and, at times, violent presidential race, ABC speculated.
The FBI says its agents are working with the US Postal Inspection Service to track down the person or people responsible for mailing these packages.
The FBI and US Postal Inspection Service are investigating a series of suspicious mailings sent to election officials in several states. Some of the letters contained an unknown substance and we are working closely with our law enforcement partners to respond to each incident and safely collect the letters.
We are also working with our partners to determine how many letters were sent, the individual or individuals responsible for the letters, and the motive behind the letters.
Click here to follow Daily Voice Berne-Westerlo-Rensselaerville and receive free news updates.