DENVER, Colorado (CNN) -- An Arapahoe County Jail inmate was charged in federal court Friday with mailing a threatening letter to Sen. John McCain's Denver, Colorado, campaign office, according to the U.S. Attorney's office in Denver.
Emergency workers outside the Sen. John McCain's headquarters in Denver, Colorado, on Thursday.
Marc Harold Ramsey, 39, will be transferred from state to federal custody to make his initial court appearance, the statement said.
According to Arapahoe County Web site records, Ramsey has been held since September 17, 2007, on charges of felony menacing, 2nd degree assault, contempt of court and being a fugitive from justice with a total bond of $352,750. He has a September 25 court date scheduled.
Staffers at the Republican presidential candidate's Denver office opened a envelope Thursday afternoon to find a threatening letter and a white, powder-like substance. Tests of the substance determined that it was not hazardous.
According to an FBI affidavit, the letter stated, "Senator McCain, If you are reading this then you are already DEAD! Unless of course you can't or don't breathe."
"A death threat is not a legitimate form of political expression," U.S. Attorney Troy Eid said. "We won't stand for threats of this kind in Colorado."
If convicted, Ramsey faces up to five years in federal prison and a fine of up to $250,000.
This month, a Florida man was arrested and charged with threatening to assassinate Sen. Barack Obama, the presumptive Democratic presidential nominee.
Raymond Hunter Geisel was arrested after classmates at a training seminar he attended told authorities Geisel told them that "if he [Obama] gets elected, I'll assassinate him myself."
A classmate also reported that Geisel said he hated President Bush and wanted to put a bullet in his head.
A search of Geisel's vehicle and a hotel room in Miami, Florida, where Geisel was attending a bail bondsman training class turned up a 9 mm handgun, ammunition that included armor-piercing and rifle bullets, police-style emergency lights, body armor, a machete and two canisters of tear gas, among other military-style items, according to the affidavit.
Geisel has pleaded not guilty.