Kristin Murphy, Deseret News
FILE - Frank E. Moss Courthouse in Salt Lake City on Friday, June 28, 2013.

SALT LAKE CITY — A convict threatened to rape a judge and bomb her Salt Lake City courthouse, prosecutors say.

Norman Eric Pierce, 47, was charged in 3rd District Court Friday with one count making a threat of terrorism, a second degree felony, and one count assault against an elected official, a class B misdemeanor.

The judge he wrote to was considering misdemeanor charges against him in April after police say he kneed an officer who arrested him after Rescue Mission workers said he refused to leave the shelter.

The same judge sentenced him to two years probation in March after he was convicted of attempting to damage a jail, but violated terms of his parole by failing to tell the court where he lived by April 10.

A warrant was issued for his arrest, and an officer arrested him April 23 at the shelter.

Pierce was booked into Salt Lake County jail April 24 for investigation of violating terms of his parole, interfering with an arresting officer, criminal trespass and assault against a police officer. He has been there since the arrest.

On May 9, a court clerk gave a letter written by Pierce to the Salt Lake County Sheriff's Department, charges state. The note to the judge identified in court documents by her initials threatened to rape her and blow up the courthouse.

A second letter allegedly from Pierce and received by the court on May 15 said he had 15 guns, "tons of ammo" and would "blow pregnant women, old people and kids away," charges state.

Court records show Pierce has a history of misdemeanor convictions.