The United States Postal Inspection Service is investigating a white powdery substance that was found in mail sent to the Stearns County Courts Tuesday morning.

Stearns County Sheriff Don Gudmundson says that a Seventh District Judicial staff reported finding a white powdery substance while opening the daily mail just before 11 a.m. 

The sheriff’s office had the United States Postal Inspection Service test the substance. The inspection services said that the sample is believed to be corn starch and contains no biologic or toxic substances. 

Further testing of the substance will be done by the Minnesota Department of Health. 

The Minnesota Bureau of Criminal Investigation will be looking into potential violations could deal with real and simulated weapons of mass destruction.