A Mississippi man who allegedly mailed poison-laced letters to the White House, a U.S. senator and a judge from Mississippi was charged Thursday with threatening the president and the two other officials, according to Justice Department documents.

Paul Kevin Curtis, 45, appeared in shackles and a Johnny Cash T-shirt at a federal courtroom in Oxford, Miss., according to the Associated Press. Although he did not enter a plea on the charges, his lawyer, Christi R. McCoy, said that Curtis “maintains 100 percent that he did not do this.”

“I know Kevin, I know his family,” McCoy said. “This is a huge shock.”

Meanwhile, another attorney who knows Curtis and once represented him said Curtis had suffered for years with a mental illness and that his family had struggled to keep him on medication to treat it.

“When he’s on his medication, he is delightful, charming, likable,” said Jim Waide, a family acquaintance who briefly represented Curtis a decade ago in a lawsuit against the medical center where Curtis worked as a janitor. “When he’s off his medication, he is paranoid and thinks people are out to get him.”

How the U.S. Postal Service checks for pathogens in mail, like ricin, sent to Congress and federal agencies.

According to an FBI affidavit supporting the charges, Curtis allegedly mailed three identical letters on yellow paper laced with a poison believed to be ricin to the White House, to the office of Sen. Roger Wicker (R-Miss.) and to a judge in Tupelo, Miss. The letters alluded to a long-held conspiracy theory that Curtis had sought to expose, having to do with trafficking in human body parts.

“No one wanted to listen to me before,” the letters read. “There are still ‘Missing Pieces’ Maybe I have your attention now Even if that means someone must die…. I am KC and I approve this message.”

The FBI documents also said that in 2007, Curtis’s ex-wife reported to police in Booneville, Miss., that her husband was “extremely delusional, anti-government, and felt the government was spying on him with drones.”

In addition to the documents, what appear to be Curtis’s writings on Internet sites describe a man who worked as celebrity impersonator east of Memphis along the Mississippi-Tennessee border, dressing up and performing at parties as Prince, Buddy Holly and Kid Rock, and most often as Elvis Presley. A decade ago, Wicker said he had hired Curtis to perform as Elvis at an engagement party.

In one online profile bearing more than 800 photos of himself, Curtis typed this in his biography: “Father/Activist/Singer/Songwriter/Business Owner/Rebel.”

But a darker world apparently also existed for Curtis, according to frequent writings on social media Web sites, legal records and a lengthy trail of letters sent previously to lawmakers from Mississippi to Capitol Hill.

The man the FBI says unnerved much of official Washington this week, leaving mail handlers, staffers and aides seeing danger in any crinkled or unmarked envelope, was also a well-practiced conspiracy theorist. He wrote online that Elvis-impersonating contests had become rigged and politicized.

Many of his diatribes revolved around conspiracy theories, on which he blamed many of the malignancies in his life. The broken relationships, the financial duress, the increasing isolation he perceived — all grew out of an episode when he was working in a morgue as a contract cleaner, according to an online post on ripoffreport.com, which was signed, “I am Kevin Curtis and I approve this message.”

According to the long, detailed post, Curtis accidentally discovered bags of body parts in the morgue and reported his finding to authorities, who immediately made him a “person of interest where my every move was watched and video taped.” He described cameras zooming in on him and said he was followed by agents.

“There was no basis for what he was saying--it was just wild,” said Waide, the lawyer, who withdrew from representing Curtis after he became convinced Curtis was mentally ill. “To me it is about mental illness, not about a criminal act.... This family has done everything it can to help him. I know his mother is very embarrassed and humiliated about it all.”

Curtis said in the post that he wrote to an array of elected officials for help, including his representative at the time, Wicker, now a U.S. senator.

“I even ran into Roger Wicker several different times while performing at special banquets and fundraisers in northeast, Mississippi,” Curtis wrote, “but he seemed very nervous while speaking with me and would make a fast exit to the door when I engaged in conversation.”

Speaking Thursday, Wicker acknowledged meeting Curtis in Tupelo. “He entertained at a party my wife and I helped to give for a young couple that was getting married,” he said. “He was quite entertaining. My impression is that since that time, he’s had mental issues and perhaps is not as stable as he was back then.”

In a Facebook post apparently authored by Curtis around 2 a.m. Wednesday — some 15 hours before federal agents arrested him in his simple brick home in Corinth, Miss. — he wrote that he was on the “hidden front lines of a secret war.”

“My mother wants me to SHUT UP. My brothers fear me. My sister hates me. . . . I have lost most of my friends,” the post reads. “I have spent more than $130,000 on legal fee’s in 13.5 years. . . . They destroyed my marriage, they distracted my career, they stalked, they trolled, they came into my home, took my computers, had me arrested 22 times and guess what? I am still a thorn in the corrupt anals! I will remain here until Jesus Christ decides its time for me to go.”

Curtis was apprehended Wednesday evening when he appeared at his home for the first time in two days, said neighbors who were outside and watched the dramatic arrest.

Latoya Brooks, 32, who lives two doors down, was in her driveway with her 10- and 13-year-old children when she said Curtis seemed to speed around the circle toward his home, stop in his driveway and return to his white SUV moments later with a duffel bag.

“All of sudden, they were coming from everywhere, huge trucks; it was scary,” said Brooks. At least three black SUVs bearing U.S. government plates sped from hiding spots through adjacent yards, pinning Curtis’s Ford from the front and the back, the neighbors said.

With guns drawn, the agents ordered Curtis to the ground and soon led him away, the neighbors said.

On Thursday afternoon, the SUV remained untouched, parked askew in the middle of Redwood Drive, a spoke off a circular neighborhood of government-subsidized housing that acquaintances said Curtis moved into late last fall.

One local law enforcement official, who spoke on condition of anonymity because he was not authorized to discuss details of the investigation, said no one had yet entered the home or processed Curtis’s vehicle for evidence.

Behind the home, yellow caution tape crisscrossed the backyard, and near the back door were some of the only items that suggested the one-story brick home was inhabited. A garden hose snaked in looping circles in the grass, and a janitor’s yellow mopping pail sat on the narrow concrete stoop.

Paul Kane and Alice Crites contributed to this report.

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