Authorities dropped charges against Paul Kevin Curtis, 45, of Tupelo, Miss., saying they found no evidence he was behind the mailing of the poison to President Obama, U.S. Sen. Roger Wicker, R-Miss., and a Mississippi county judge, CNN reported.
"It's like a train has been lifted off my shoulders," Curtis told CNN's "Piers Morgan Live" Tuesday. "I'm overwhelmed. I'm extremely happy to be vindicated and out and able to see my kids."
Lawyers for Curtis said he had been framed by J. Everett Dutschke, whom authorities said was a person of interest in the case. Dutschke is a martial arts instructor and is considered a longtime personal enemy of Curtis,' Tupelo's Northeast Mississippi Daily Journal reported.
"I do believe that someone who was familiar and is familiar with Kevin just simply took his personal information and did this to him," said Christi McCoy, Curtis' lawyer. "It is absolutely horrific that someone would do this."
"I think now, how many people are thrown in jail because of circumstantial evidence and someone can frame you that easily," Curtis said.
It isn't immediately clear why the two men clashed but Curtis said they exchanged angry email messages to each other for years.
A law enforcement official told The Wall Street Journal the FBI wanted to find out if the alleged feud between the two men was behind the letters sent to Washington.
The National Guard searched Dutschke's neighborhood and house Tuesday, though have brought no charges against him, the Daily Journal said.
Dutschke, 41, has denied involvement in the incident.
Dutschke attorney Lori Nail Basham was quoted by The Wall Street Journal as saying her client was "cooperating fully" and hadn't been charged with any wrongdoing.
At a news conference after his release, Curtis, 45, a celebrity impersonator, said he had no ill feelings toward prosecutors or the president and was glad to be free.
"I respect President Obama," he said. "I love my country and would never do anything to pose a threat to him or any other U.S. official."
Dutschke was arrested in January on charges of child molesting. He was released on $25,000 bond and is awaiting trial.
He ran for the lower house of the state Legislature in 2007 but lost to incumbent Steve Holland. Holland's mother, Sadie Holland, is the county judge who received one of the letters.