Matthew Unglesbee is charged with mailing threatening communications and mailing false information and hoaxes. The letters went to the offices of U.S. Reps. Jan Schakowsky in Skokie, Mike Quigley in Chicago and Brad Schneider in Lincolnshire. Schakowsky’s office received suspicious mail twice within a week, and hazmat teams and the FBI responded to the incidents.

The first three envelopes contained a white granular substance and handwritten notes reading “HA HA,” court records say. A fourth, reported two days later, contained a similar substance and a note reading “HAH enjoy the gift.” The envelopes had handwritten addresses and were postmarked in Springfield. Their return addresses named Unglesbee and matched an address listed for him in government records.

Testing found the substance was not harmful or toxic, according to law enforcement. During an FBI interview, Unglesbee acknowledged mailing the letters and said the substance was salt, court records say. He told agents he had heard someone in a restaurant discussing news reports about similar mail sent to lawmakers, including Sen. Amy Klobuchar and Senate Minority Leader Chuck Schumer. He denied involvement in letters sent to members of Congress outside Illinois.

The investigation began after an anonymous tipster told the FBI that Unglesbee had said he mailed letters to members of Congress around the country, according to an affidavit. The court documents say the FBI was notified after three lawmakers reported receiving envelopes with suspicious powder.

The Adams County Sheriff’s Office said Unglesbee was being held in its jail on state charges of harassment through electronic communications. A date for his federal court appearance was not immediately available.