Nassau Police investigate a suspicious substance at the Nassau County...

Nassau Police investigate a suspicious substance at the Nassau County Courthouse on Monday in Mineola. Credit: Howard Schnapp

The Nassau County Court in Mineola was evacuated late Monday afternoon after a mail room employee opened an envelope with white powder inside later deemed to be harmless, officials said.

Nassau County police are investigating the call that led to the evacuation of the courthouse shortly before 5 p.m. and said later Monday the substance was found to be "non-hazardous material."

The Nassau County district attorney's office in the criminal courthouse was also evacuated, officials said.

A state court spokesman said the powder appeared to come from a state prison inmate who sent envelopes to various sites around the state.

“It is not anthrax. It appears to be an inert substance," state courts spokesman Lucian Chalfen said.

With Bridget Murphy

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