The Miami Police Department was quarantined Friday evening after a suspected anthrax threat.
Authorities say a Miami resident found an envelope with faded writing on the front that suggested the contents of the envelope might be anthrax.
Because the envelope was brought to the police department, employees there were quarantined throughout the investigation.
A hazardous-materials team was called in and tests showed that the envelope contained a common biscuit mix.
Last week, the hazardous-material team was called to investigate the contents of a suspicious enveloped delivered to Integris Baptist Regional Health Center.
The envelope arrived the day after three hospitals in Oklahoma, including Craig General Hospital in Vinita, were evacuated because of suspicious mail.
The return address on the envelopes were a company from the east coast, who say they had nothing to do with it.
The Department of Homeland Security visited all three hospitals to test the powder - it turned out to be garlic powder.
The investigation continues as to the origin of the suspicious envelopes.