An Ames man was arrested over the weekend after court documents indicate that he made an anthrax threat against a Nevada teacher, mailing an envelope to the teacher filled with a white powder.

Mondell V. Olson, 66, is charged with first-degree harassment.

According to court documents, Olson sent a letter to Nevada Central Elementary School on March 21, addressed to the victim. Documents allege that Olson crushed up his prescription medication and placed it in the envelope, with a note saying “ANTHRAS.”

Court documents show that the victim feared the powder was anthrax and alerted police.

Olson was previously arrested and charged with harassing a transgender student at Nevada High School in February 2017. In that case, Olson was also charged with multiple counts of first-degree harassment and eventually pleaded guilty to one count of first-degree harassment and one count of third-degree harassment.

Olson was sentenced to 30 days in jail and fined $625 in May 2017, and placed on a probationary period of one year.

Story County Attorney Jessica Reynolds said that Olson’s probation officer successfully petitioned the court to take him off probation last month.

As of Monday afternoon, Olson remained held in Story County Jail on $10,000 bond.

His preliminary hearing is set for April 3.