KEY WEST, Fla. - Key West police locked down the post off on Whitehead Street Friday after someone found a "threatening letter" with a white substance inside the package.
The city's hazardous materials team responded about 12:47 p.m. and the people inside went through a decontamination process.
Several people were taken to Lower Keys Medical Center as an added precaution.
The post office didn't reopen Friday.
The FBI is investigating.
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