Charges of sending ricin-laced letters to U.S. President Barack Obama and others were dropped Tuesday against an Elvis Presley impersonator from Mississippi who has said since his arrest last week that he had nothing to do with the case.

Meanwhile, in Tupelo, numerous law enforcement officers converged on the home of another Mississippi man, Everett Dutschke, including some in hazardous material suits. No charges have been filed against him and he hasn't been arrested. Both men say they have no idea how to make the poisonous ricin and had nothing to do with sending them to Obama, U.S. Senator Roger Wicker of Mississippi and a state judge.

Referring to officials' questions for him about the case, "I thought they said rice and I said I don't even eat rice," 45-year-old Paul Kevin Curtis said after he was released from custody Tuesday afternoon. "I respect President Obama. I love my country and would never do anything to pose a threat to him or any other U.S. official."

An FBI agent stops homeowner James E. Dutschke from approaching his home Tuesday in Tupelo, Miss. Agents searched Dutschke's home in connection with the ricin letters sent to U.S. Senator Roger Wicker and President Barack Obama. (Thomas Wells/Northeast Mississippi Daily Journal/Associated Press)

A one-sentence document filed by federal prosecutors said charges against Curtis were dropped, but left open the possibility they could be reinstated if authorities found more to prove their case. Prosecutors were not immediately available for comment.

The dismissal is the latest twist in a case that rattled the country already on edge over the Boston Marathon bombing last week.

Curtis was well-known to Wicker because he had written to the Republican and other officials about black-market body parts he claimed to have found while working at a hospital — a claim the hospital says is untrue. Curtis also wrote a book called Missing Pieces about his claims and posted similar language on his Facebook page and elsewhere. The documents indicate Curtis had been distrustful of the government for years.

He told The Associated Press Tuesday that he realizes his writings made him an easy target.

"God will get the glory from here on out. It's nothing about me. It's nothing about my book. It's nothing about the hospital. After 13 years of losing everything I have turned it over to God. After all these years God was the missing piece," Curtis said.

No evidence found in home searches

The two men the FBI are investigating are not strangers. Dutschke said the two had a falling out and that the last contact they had was in 2010. Dutschke said he threatened to sue Curtis for saying he was a member of Mensa, a group for people with high IQs.

Since Curtis's arrest at his Corinth home on April 17, his attorneys have said their client didn't do it and suggested he was framed. An FBI agent testified in court this week that no evidence of ricin was found in searches of Curtis's home.

Dutschke said in a phone interview with the AP that the FBI was at his home for the search connected to the mailings. Dutschke said his house was also searched last week.

"I don't know how much more of this I can take," Dutschke said.

Curtis attorney Hal Neilson said the defence gave authorities a list of people who may have had a reason to hurt Curtis.

"Dutschke came up," he said. "They (prosecutors) took it and ran with it. I could not tell you if he's the man or he's not the man, but there was something there they wanted to look into."

An FBI intelligence bulletin obtained by The Associated Press said the two letters to Obama and Wicker said: "To see a wrong and not expose it, is to become a silent partner to its continuance." Both were signed, "I am KC and I approve this message."

Multiple online posts on various websites that could be seen by anyone under the name Kevin Curtis refer to the conspiracy he claimed to uncover when working at a local hospital from 1998 to 2000. In one post, Curtis said he sent letters to Wicker and other politicians. He signed off: "This is Kevin Curtis & I approve this message."

'Diabolical' plot to frame client, lawyer says

Curtis attorney Christi McCoy said she doesn't know what new information prosecutors have and that the plot to frame her client was "very, very diabolical."

Curtis, dressed in a black suit, red shirt, necktie and sunglasses, said he met Dutschke in 2005 but for some reason Dutschke "hated" and "stalked" him. "To this day I have no clue of why he hates me."

Dutschke has maintained his innocence and says he doesn't know anything about the ingredients for ricin. Ricin is derived from the castor plant that makes castor oil. There is no antidote and it is at its deadliest when inhaled. It can be aerosolized, released into the air and inhaled. The Homeland Security handbook says the amount of ricin that fits on the head of a pin is enough to kill an adult if properly prepared.

Dutschke said agents asked him about Curtis, whether Dutschke would take a lie detector test and if he had ever bought castor beans, which can be used to make the potent poison.

"I'm a patriotic American. I don't have any grudges against anybody. I did not send the letters," said Dutschke, who was a Republican candidate for the Mississippi house of representatives in 2007 but lost.

After charges were dropped against Curtis, he said: "I'm a little shocked."

Dutschke said his attorney wasn't with him and he didn't know whether he was going to be arrested.

Tuesday's events began when the third day of a preliminary and detention hearing was cancelled without officials explaining the change. Within two hours, Curtis had been released, though it wasn't clear why at first.

FBI agent Brandon Grant said in court on Monday that searches last week of Curtis's vehicle and house in Corinth, found no ricin, ingredients for the poison, or devices used to make it. A search of Curtis's computers found no evidence he researched making ricin. Authorities produced no other physical evidence at the hearings tying Curtis to the letters.

All the envelopes and stamps were self-adhesive, Grant said Monday, meaning they won't yield DNA evidence. One fingerprint was found on the letter sent to a Lee County judge, but the FBI doesn't know who it belongs to, Grant said.

The experience, Curtis said, has been a nightmare for his family. He has four children — ages, 8, 16, 18 and 20. It also has made him reflect deeply on his life.

"I've become closer to God through all this, closer with my children and I've even had some strained relationships with some family and cousins and this has brought us closer as a family," he said.