The Key West Post Office on Whitehead Street was evacuated on Friday after a package with a threatening note and suspicious powder was received.
Authorities were notified about the package at about 12:47 p.m., and more than a dozen people at the post office are being decontaminated as a precaution. NBC 6 received photographs of the alleged note and envelope. It is confirmed that the person whose name is on the envelope is currently incarcerated in Maryland for a bank robbery, in which he threw gasoline at the tellers.
Several people who were closer to the powder are being transported to the Lower Keys Medical Center as an added precaution.
"People who were closer are being transported in case it is an anthrax contamination," said Alyson Crean, City of Key West spokeswoman.
Police have cordoned off the property and closed the 400 block of the street.
The post office will not open this afternoon.
Once the evacuation is finished, the hazardous materials teams will enter the building to determine the threat, Crean said.
Authorities are urging the public to avoid the area.
The FBI will be investigating the situation.
Stay with NBC6.com for updates.