PORTLAND, Oregon A former nurse from Vancouver, Washington, was sentenced to two years in prison on Wednesday for mailing more than 100 threatening letters containing white powder to members of Congress and media organizations in February of 2012.
Christopher Carlson, 41, pleaded guilty to a charge of conveying false information and a hoax purporting to expose recipients of the letters to a biological toxin in a mass mailing that set off coast-to-coast anthrax scares.
White powder contained in the envelopes, postmarked from Portland, Oregon, was later revealed to consist of celery salt and corn starch, the U.S. attorney for Oregon said in a statement about the sentencing.
The letters were sent to congressional offices on Capitol Hill, and their field offices across the country, as well as to various media outlets, including The New York Times, National Public Radio and "The Daily Show with Jon Stewart."
About two dozen of the letters were received and opened by staff members before law enforcement was able to intercept the remainder.
The mailing triggered a flurry of evacuations, the dispatch of hazardous materials squads and decontamination procedures, with dozens of police and emergency medical teams responding in 24 federal districts, authorities said.
The threatening letters "expressed frustration with politicians, corporations and lobbyists" and promised a "new American revolution," according to the statement from the U.S. Attorney's Office.
Some also included the warning message: "Oh yeah, the powder. 50 Senators were randomly selected to received this letter as opposed to the other one. Since I put the bug in ten of these letters, again randomly selected, there's a 20% chance that you've just been exposed. If you aren't wearing a biohazard suit, anyway."
Carlson was arrested at his home in March, about a month after the mailing, and had been jailed without bond since then. He had worked as a registered nurse, then as a trainer in electronic recordkeeping at a Vancouver hospital, just across the Columbia River from Portland, until taking a leave of absence in December 2011.
The security alert he set off marked the biggest postal scare in the nation's capital since deadly anthrax-laced letters were sent to several news organizations and Senate offices in 2001 in the wake of the September 11 attacks on the World Trade Center and Pentagon.
Five people were killed and 17 sickened by those letters, which federal investigators ultimately traced to a U.S. Army scientist who committed suicide in 2008.
In addition to his two-year prison term, Carlson was ordered to pay $36,310 in restitution for the cost of emergency responses his mailings triggered.
In sentencing Carlson, the judge said he was taking into account the defendant's now-diagnosed bipolar disorder, and the testimony of a psychiatrist that Carlson committed the hoax in the midst of a manic episode, the Oregonian newspaper reported.
Carlson apologized in court in court "to all the people that I scared, all the government resources I wasted, all the havoc that I caused," adding that "I wasn't right in the head," according to the newspaper.
(Reported by Teresa Carson; Editing by Steve Gorman and Eric Walsh)