(Reuters) - Federal prosecutors have charged a Colorado man with threatening gun violence and arson against staffers of U.S. Senator Michael Bennet in the days before an unrelated shooting rampage that left an Arizona congresswoman gravely wounded.
The suspect, John Troy Davis, 44, made a brief appearance before a federal magistrate in U.S. District Court in Denver on Monday and was ordered to remain in custody until his next court date on Thursday to set terms of his bond.
Handcuffed to a waist-chain and sporting a goatee, Davis answered, "Yes, sir," when asked by the judge if he understood the proceedings. He then asked, "Who's my lawyer?" and was assigned a public defender.
He is charged with one count of assault on a federal employee stemming from a series of threats he is accused of making over the telephone to three staffers in Bennet's Denver office. If convicted, Davis faces up to 10 years in prison.
According to an FBI affidavit filed with the criminal complaint against him, Davis was known to Bennet's staff for frequent calls to his office seeking help with problems he said he was having with his Social Security benefits.
The FBI says he grew increasingly irate in recent phone conversations, telling a staffer in one call last Thursday that he was a schizophrenic and was "going to come down there and shoot you all." He threatened in a separate call to "go down there and set fire to the perimeter" and further stated he "may go to terrorism," the FBI alleged.
Davis was arrested over the weekend.
Investigations of such threats are relatively commonplace. Federal prosecutors said they had charged two unrelated individuals with making threats against Obama last week alone.
But the case involving Bennet's office came amid heightened concerns for the safety of lawmakers following the attack on Congresswoman Gabrielle Giffords, a Democrat, in her Tucson district on Saturday. Six people died in that shooting.
The FBI said additional security has been provided at Bennet's home and office in Denver because of the threats.
Bennet, a Democrat, was appointed to the Senate in 2009 to fill the seat vacated when Ken Salazar was named U.S. interior secretary. He was elected to a six-year term of his own in November in a race against Republican Ken Buck.
"Michael has full confidence in the law enforcement agencies handling the case and remains focused on his job serving the people of Colorado," Bennet's spokesman, Adam Bozzi, said in a statement.