The Linn County Courthouse was closed Monday after an early morning anthrax scare, which proved to be a hoax in the end.

Around 6:15 a.m., a custodian found a note on an outside door noting the presence of envelopes containing anthrax inside and outside the courthouse. The message on the note claimed there were 10 other envelopes inside the building, local media sources reported.

“The note indicated that anthrax was in envelopes in the courthouse,” Linn County Sheriff Tim Mueller said.

Just one person, a clerk, was in the building when the note was found, but that person got out safely.

Following the note, all 29-court hearings were canceled for the day. Members of the Linn-Benton Haz-Mat team, Army National Guard, FBI and the Department of Homeland Security were called to investigate the scene and identify the substance.

Only two envelopes connected to the note were found, one slid under a door and the other left with the note outside.

The investigators took the envelopes to a mobile testing center, where results indicated the substance was not anthrax, but something resembling granulated white sugar. A portion of the substance was taken to the FBI lab in Portland for further testing.

There are no suspects in the case, but authorities said a criminal investigation is underway. Those involved could face felony charges.

The courthouse is expected to reopen Tuesday morning.