A 45-year-old man has pleaded guilty to sending a threatening note to a New London judge in September 2010 along with a substance he said was “liquid Anthrax” and to making a bomb threat that resulted in the evacuation of the Thomaston Post Office.

Roland Prejean, also known as Gary Joseph Gravelle, 45, pleaded guilty before U.S. District Judge Warren W. Eginton to one count of using the U.S. mail to communicate a bomb threat and four counts of mailing threatening communications. Prejean faces a maximum of 35 years in prison when he is sentenced April 8.

Prejean, who lived in Thomaston and Morris, has been in federal custody since he was arrested in North Dakota on Sept. 7, 2010, after mailing more than 50 threatening letters, according to the office of U.S. Attorney David B. Fein.

On Sept. 4, 2010, Prejean sent a letter to an unnamed Superior Court judge at the courthouse at 70 Huntington St. in New London, according to court documents. The letter contained a substance labeled “liquid Anthrax.”

“Hello. My name is Roland Prejean and I am the man who is going to kill you,” the letter began. Prejean went on to say that he had just spent six years at Connecticut Valley Hospital and that the judge had committed “wrongs against some of my people.”

Prejean also sent a threatening letter to the Thomaston Post Office claiming he had planted a hidden bomb there with a remote timer. The post office and a nearby school were evacuated as bomb technicians searched for explosive devices. Nothing was found.

“We will vigorously investigate and prosecute hoax crimes that threaten violence,” said Fein. “These crimes cause emotional distress for victims and waste the valuable time and resources of our law enforcement community.”