Darien emergency officials, along with the FBI and State Police Emergency Services, are investigating after a resident of the Tokeneke section of Darien received a threatening letter containing white powder.
According to police, the resident called emergency services around 2:30 p.m. to report the delivery of a suspicious letter.
Police said the letter contained white powder and that nine people were exposed, but so far, none have exhibited any symptoms of illness.
Investigators are working to determine who sent the letter and why.
The investigation is ongoing.