OXFORD, Miss. - A Mississippi man charged with sending ricin-laced letters to the president and other officials was described Thursday as a good father, a quiet neighbor and an entertainer who impersonated Elvis at parties. Other accounts show a man who spiraled into emotional turmoil trying to get attention for his claims of uncovering a conspiracy to sell body parts on the black market.

Paul Kevin Curtis, 45, wrote numerous Web posts over the past several years describing the event that he said "changed my life forever": the chance discovery of body parts and organs wrapped in plastic in small refrigerator at a hospital where he worked as a janitor more than a decade ago.

He tried to talk to officials and get the word out online, but he thought he was being railroaded by the government. Authorities say the efforts culminated in letters sent to President Barack Obama, a U.S. senator and a judge in Mississippi. "Maybe I have your attention now even if that means someone must die," the letters read, according to an FBI affidavit.

"He is bipolar, and the only thing I can say is he wasn't on his medicine," his ex-wife, Laura Curtis, told The Associated Press.

Jim Waide, an attorney for the Curtis family, said Paul Kevin Curtis was prescribed medication three years ago. "When he is on his medication, he is terrific, he's nice, he's functional," Waide said. "When he's off his medication, that's when there's a problem."

Waide represented Curtis in a lawsuit he filed in August 2000 against North Mississippi Medical Center in Tupelo, where he had worked from 1998 until he was fired in 2000. Waide said he withdrew from the case because Curtis didn't trust him. The suit, claiming employment discrimination, was dismissed.

"He thought I was conspiring against him," Waide said. "He thinks everybody is out to get him."

Curtis made a brief court appearance Thursday, wearing shackles and a Johnny Cash T-shirt. Attorney Christi R. McCoy said he "maintains 100 percent" that he is innocent. He did not enter pleas to the two federal charges against him. He is due back in court Friday afternoon.

In several letters to U.S. Sen. Roger Wicker, a Mississippi Republican, and other officials, Curtis said he was writing a novel about black-market body parts called "Missing Pieces."

Curtis also posted similar language on his Facebook page. The documents indicate Curtis had been distrustful of the government for years. In 2007, Curtis' ex-wife called police in Booneville to report that her husband was extremely delusional, anti-government and felt the government was spying on him with drones.

Laura Curtis said that she doesn't believe the allegations about her ex-husband. "He just likes to speak out," she said.

"What they say he did is so unlike him, it's unreal," she added. "Until I hear him say he did it, I would not, ... I could not believe it."

During their 10-year marriage, the couple lived in Booneville in north Mississippi. Curtis said she moved to a house next door after the split. Her ex-husband moved to Birmingham but eventually back to Mississippi, most recently the small town of Corinth, where he was arrested Wednesday. Laura Curtis said he would visit their four children - ages, 8, 16, 18 and 20 - almost every day. He recently bought his youngest child a bicycle.

But others say Curtis' behavior was often erratic.

Tupelo attorney David Daniels said Curtis was in a show he helped organize about 10 years ago.

Daniels said was sitting in his vehicle one night after rehearsal when Curtis walked up. "He started beating on the windows and screaming and hollering," Daniels said. "I thought he was kidding, but he was serious. He was throwing a fit like I've never seen a grown man throw before."

Daniels said Curtis was holding a beer bottle and threatening him with it. Daniels said he pointed the pistol he kept in his car: "I told him, 'If you try to hit me with that bottle, Kevin, I'm going to shoot you."'

But he said Curtis stayed by the vehicle for as long as 15 minutes. "He was screaming and ranting and raving about body parts being sold," Daniels said.

Daniels eventually filed simple assault charges and he said the judge who handled the case was Sadie Holland - one of the three people who received a letter suspected of containing ricin, according to authorities. Records show she sentenced Curtis to six months in the county jail.

Daniels was an assistant district attorney at the time. "He launched a smear campaign against me, saying I attacked him and tried to shoot him," Daniels said Thursday.

"It made my life miserable for almost two years, having to deal with this guy," he said.

On Thursday, North Mississippi Medical Center confirmed Curtis' employment and said in a statement he was not terminated in response to allegations about the facility.

Under the name Kevin Curtis, multiple online posts describe the conspiracy Curtis claimed to uncover when working there. The posts say the conspiracy began when he "discovered a refrigerator full of dismembered body parts & organs wrapped in plastic in the morgue of the largest non-metropolitan health care organization in the United States of America."

The hospital's statement says it works with an agency that specializes in harvesting organs and tissue from donors, and then immediately transports those organs for donation. The hospital says it does not receive payment for the donated organs.

In one post, Curtis said he sent letters to Wicker and other politicians.

"I never heard a word from anyone. I even ran into Roger Wicker several different times while performing at special banquets and fundraisers in northeast, Mississippi but he seemed very nervous while speaking with me and would make a fast exit to the door when I engaged in conversation ... "

Wicker said Thursday in Washington that he had met Curtis when he was working as Elvis at a party Wicker and his wife helped throw for an engaged couple about 10 years ago.

Wicker called him "quite entertaining" but said: "My impression is that since that time he's had mental issues and perhaps is not as stable as he was back then."

Early Thursday evening, the FBI said lab tests confirmed the presence of ricin in the letters mailed to Obama and Wicker.

At least a dozen armed officers wearing gas masks and hazardous-material suits went into Curtis' home Thursday evening in Corinth. There was no immediate word on what they found inside.

Police had blocked off the home with crime-scene tape since Wednesday's arrest. No neighbors have been evacuated.

Raymond Zilinskas, a chemical and biological weapons expert at the James Martin Center for Nonproliferation Studies in California, called the process to make ricin elaborate. He said it would not be difficult to create a low-concentration version using instructions from the Internet, but a finer and more concentrated version would require laboratory equipment and expertise.

Laura Curtis said she doesn't think her ex-husband has the knowledge required to make ricin. She said he collects a monthly disability check, and she did not know where he would get ricin.

She said she cried when she heard about the arrest.

"It's more sinking in today, because you see the longer picture," Curtis said. "It's just me and the kids."

Associated Press Photographer Rogelio Solis in Corinth; writers Emily Wagster Pettus in Jackson; and Eric Tucker and Jessica Gresko in Washington contributed to this report.