Investigators trying to determine who sent ricin-tainted letters to President Obama and other officials quickly traced the messages and signature of the letter to Paul Kevin Curtis, an Elvis impersonator who had written to officials in the past and consistently signed his letters "I am KC and I approve this message," according to an FBI affidavit.
Curtis, 45, was arrested at his home in Corinth, Miss., just a day after a letter laced with the poison arrived at the office of Sen. Roger Wicker, R-Miss. A second letter was sent to President Obama and a third letter was mailed to Sadie Holland, a justice of the peace in Lee County, Miss.
About 15 members of a hazmat team, some totting M4 rifles, entered Curtis' house today and set up an evidence-gathering area outside.
Curtis was formally charged today with sending mail that contained a threat to kill or harm the president and with sending mail containing a threat to injure the president.
He was arraigned in federal court in Oxford, Miss., where he arrived in court wearing shackles and a Johnny Cash T-shirt.
The suspect said little, but his attorney, Christi R. McCoy, said Curtis "maintains 100 percent that he did not do this," according to the Associated Press. She said she knows him and his family and that it is hard for her to believe the charges against him.
But court affidavits claimed that investigators quickly matched the verbiage used in the ricin tainted letters to Curtis' online postings and previous letters to government officials.
Investigators particularly focused in on the signature, "I am KC and I approve this message," and his mention of "Missing Pieces."
According to the affidavit, the letter sent to Wicker and Obama read:
No one wanted to listen to me before.
There are still 'Missing Pieces'
Maybe I have your attention now
Even if that means someone must die.
This must stop.
To see a wrong and not expose it,
Is to become a silent partner to its continuance
I am KC and I approve this message
The FBI asked Wicker's office to see if it had any prior correspondences with constituents who had the initials "KC," which revealed multiple letters previously sent by Curtis to Wicker's office, according to the affidavit. All of the letters ended with a variation of the same signature, according to court documents filed today.
Curtis also frequently wrote about an alleged black market for the illegal sale of human body parts, which he believed the government was covering up, the affidavit said. He wrote about the allegations in an unpublished novel called "Missing Pieces," which he discussed on his Facebook page and in the letters to government officials, according to the FBI.
Curtis had previously written an e-mail to Rep. Alan Nunnelle of Mississippi in which he also mentioned "Missing Pieces."
The ricin letters and Curtis' Facebook page contained identical refrains: "To see a wrong and not expose it, is to become a silent partner to its continuance."
Wicker acknowledged today that in addition to the letters Curtis had sent him, the two had met once. Wicker hired Curtis, an Elvis impersonator and entertainer, to perform at a party Wicker threw, he told reporters in Washington.
Curtis made a living impersonating music stars and putting on shows. He dressed up as Elvis, Hank Williams Jr., and Prince, according to his Facebook profile and YouTube videos.
"I have worked tirelessly to perfect an art form & unique show for all ages with ... authentic costumes songs, gimmicks & props," he wrote on his Facebook page, noting that he had developed a Tribute to the Stars show featuring Elvis, Buddy Holly, Johnny Cash and others.
"Complete with authentic Costumes, lights, lasers, Strobes & plenty of audience interaction!" he wrote.
Curtis believed in cover-ups, according to his ex-wife, who reported him to police in 2007 for being "extremely delusional, anti-government, and (for feeling) the government was spying on him with drones," according to the affidavit.
He wrote on his Facebook profile that if the federal government were "using or monitoring/using this website or any of its associated websites, (they) do NOT have permission."
After two bombs exploded at the finish line of the Boston Marathon on Monday, Curtis addressed the crime on his Facebook page.
"This world is not what it used to be and the hopes of all are not what they 'USED' to be. We have let God down. We removed prayer from schools in 62 ... we have staged wars simply for profits in oil and drugs ... we have lied our way from the capitol to the pulpit. We the people should be ashamed. I weep for the future of our children. God bless."
Curtis's family did not return messages left seeking comment. His brother said in a written statement Wednesday that the family had "no reason to believe Kevin would be involved," but that relatives knew "very little" about the case.
"Until my family gets some answers and we have a chance to talk to my brother, I can't comment further," Jack Curtis wrote.
ABC News' Matt Gutman contributed to this report.