Federal prosecutors on Thursday filed criminal charges against Paul Kevin Curtis, the Mississippi man who was arrested a day earlier in the FBI's investigation of letters believed to contain the deadly poison ricin.
A criminal complaint filed in U.S. District Court for the Northern District of Mississippi charges Curtis with threatening to harm President Barack Obama and making other threats through the Postal Service.
Curtis is expected to appear in court Thursday.
He was arrested at his home in Corinth, Miss., and is "believed to be responsible for the mailings of the three letters sent through the U.S. Postal Inspection Service which contained a granular substance that preliminarily tested positive for ricin," the Justice Department said in a statement.
The letters were addressed to a U.S. senator, the White House and a Mississippi justice official, the statement said.
The ricin poison scare hit Washington after bombings at the Boston Marathon killed three people and injured 176 on Monday, but the FBI said there was no indication the incidents were connected.
The FBI said the envelope sent to Obama was received at a mail-screening facility outside the White House and was immediately quarantined. Preliminary tests showed it contained the deadly poison ricin, the FBI said.
Washington was put on edge Tuesday evening when news emerged that authorities had intercepted a letter sent to Republican Sen. Roger Wicker of Mississippi that had initially tested positive for ricin.
Following the arrest, Wicker issued a statement thanking the FBI and Capitol Police "for their professionalism and decisive action in keeping our family and staff safe from harm."
Earlier on Wednesday, a flurry of reports of suspicious letters and packages rattled the U.S. capital and caused the temporary evacuation of parts of two Senate buildings. Most of the reports quickly proved to be false alarms, and business was only temporarily disrupted on Capitol Hill.
The letters to Obama and Wicker had identical language, including the phrase, "To see a wrong and not expose it, is to become a silent partner to its continuance." They were signed, "I am KC and I approve this message," according to an FBI operations bulletin reviewed by Reuters.
Two law enforcement sources said investigators believed the man arrested was the same person as Kevin Curtis, who they say has posted rants on the Internet and performed as an entertainer and Elvis Presley impersonator.
In an online comment on an Elvis blog post in 2007, a Kevin Curtis complained that several Elvis contests in several states "were rigged with hosts and judges getting kick-backs." The signature was: "This is Kevin Curtis and I approve this message."
Northern District Mississippi Public Service Commissioner Brandon Presley, who said he was related to Elvis Presley, told Reuters that Curtis contacted him via Facebook late Sunday, asking if he was a relative of the late rock singer.
Presley said he did not know Curtis. "I don't know if he's fixated on Elvis or Elvis' family or what," he said. "We've been told by the authorities to be very cautious with our mail for the next few days."
Public records show a Paul Kevin Curtis lived until recently in Booneville, Miss. Randy Tolar, a sheriff in Prentiss County, where Booneville is located, said he knew a Paul Kevin Curtis who had been jailed at least four times in recent years, all on misdemeanor charges, including telephone harassment and stalking.
The envelopes believed to contain ricin both bore postmarks from Memphis, Tenn., and were dated April 8. Memphis Mayor A.C. Wharton noted in a statement, however, that it did not mean the letters originated in that city.
An aide to Wharton said many areas near Memphis were included in its postmark — including some in neighboring northern Mississippi, Wicker's state.
For Washingtonians, the situation was an unsettling reminder of events of nearly 12 years ago when letters containing anthrax spores were mailed to the Washington offices of two senators and to media outlets in New York and Florida, not long after the Sept. 11, 2001, attacks in New York and Washington.
The FBI said White House operations were not affected by the latest scare. It noted that filters at a second government mail-screening facility had preliminarily tested positive for ricin this morning" and mail from that facility was also being tested.
The tests were being conducted at Fort Detrick, in Frederick, Md., a government source said.
White House spokesman Jay Carney said Obama had been briefed on the situation.
Ricin is a lethal poison found naturally in castor beans, but it takes a deliberate act to convert it into a biological weapon. Ricin can cause death within 36 to 72 hours from exposure to an amount as small as a pinhead. No known antidote exists.
There was another ricin scare at the U.S. Capitol in 2004, when tests showed positive on a letter in a Senate mail room that served the office of Bill Frist, a Tennessee Republican who was then Senate majority leader.
Series of suspicious items
Law enforcement authorities Wednesday closed and then reopened parts of the Hart and Russell Senate buildings near the Capitol after tests on suspect items showed there was no threat.
"All test results were negative," U.S. Capitol Police said over the public address system in Senate office buildings.
Police questioned a man with a backpack who had been delivering envelopes to Senate offices, a law enforcement official said. This delivery method broke the normal protocol, because no mail is supposed to be delivered without first being checked at an outside facility, Capitol officials said.
In Arizona, the bureau of Alcohol, Tobacco, Firearms and Explosives said two suspicious letters had been sent to Republican Sen. Jeff Flake's Phoenix office. Two staffers and a police officer were taken to the hospital as a precautionary measure after reporting irritation when handling them.
Flake later issued a statement Wednesday saying no dangerous materials were detected in the mailings. One of them originated in Tennessee, Flake told reporters outside the Senate.
In Ohio, Columbus police responded to a report of a suspicious letter received Wednesday at Republican Sen. Rob Portman's office, but determined it was not dangerous, Portman's office said.
Democratic Sen. Carl Levin said one of his Michigan regional offices had also received a suspicious letter, but it was not opened. Authorities are investigating, and a staff member went to the hospital as a precautionary measure, he said.
It is unclear if there was a connection linking the series of suspicious items delivered to politicians.
The Senate's sergeant at arms, Terrance Gainer, sent a memo to all offices telling them only to accept mail from a uniformed Senate post office employee and, when in doubt, to call the police.
He said mail was being delivered that had already been cleared, but there would be no mail delivered Thursday and Friday to allow for more testing and investigation.