After keeping Elvis impersonator Paul Kevin Curtis in jail for a week, interrogating him while he was chained to a chair and turning his house upside down, federal authorities had no confession or physical evidence tying him to the ricin-laced letters sent to President Obama and other public officials.

Investigators already had another man in their sights and, according to an FBI affidavit, were collecting physical evidence against this second suspect. It was beginning to look as if Curtis had been framed.

But instead of setting Curtis free, court records show, federal officials sought to keep him in custody.

First, three days after the arrest, prosecutors asked for a psychiatric evaluation — a request usually made by defense lawyers. That could have extended his stay in federal prison by several months and allowed investigators to continue to question him.

Then, after a judge denied the request, federal prosecutors filed a motion seeking to postpone a court hearing at which they would be required to reveal the evidence they had against Curtis. That was also turned down.

Booking photo of James Everett Dutschke taken January 18, 2013, provided by the Tupelo, Miss., Police Department. (AFP/GETTY IMAGES)

“They wanted to keep Mr. Curtis in custody while they built a case,” said Hal Neilson, a former FBI agent who is Curtis’s attorney. “They knew early on he wasn’t the right guy, but they fought to hold on to him anyway.”

The FBI and the U.S. Attorney’s Office in Oxford, Miss., did not respond to requests for interviews or to written questions.

An official with the federal court, speaking on the condition of anonymity, said Neilson’s characterization of the prosecutor’s request for a psychiatric examination and for a postponement were accurate and that they were viewed by the court as unnecessary delays.

Curtis was arrested April 17 after coming to the attention of federal investigators. The ricin-laced letters had closed with the sentence “I am KC and I approve this message” — language very similar to that in letters Curtis previously had written to public officials. Phrases in the ricin letters also matched those on Curtis’s Facebook page.

Investigators had no other evidence against him, according to the FBI affidavit and court testimony. At a hearing a week later, after prosecutors unsuccessfully asked to keep him under house arrest and again tried to postpone the hearing, Curtis was released and charges of threatening the president and other elected officials by mailing ricin-laced letters were dropped.

On Saturday, the second suspect, James Everett Dutschke, was arrested at his home and accused of making ricin and placing it in letters he sent to Obama, Sen. Roger Wicker (R-Miss.) and Justice Court Judge Sadie Holland of Mississippi’s Lee County. Dutschke, who faces a life sentence if convicted, pleaded not guilty this week to a charge of attempting to use a biological weapon.

Echoes of anthrax case

Amid intense public and political interest in the ricin case, federal investigators began focusing on Curtis after staffers in Wicker’s Senate office said they had previously received correspondence from him with language similar to the poisoned letters. The ricin letters also seemed to allude to Curtis’s unpublished novel, “Missing Pieces,” about black-market trading in human body parts, which he had mentioned on his Facebook page.

“This was all available for anyone to see,” Curtis said in an interview. “I guess it was easy to frame me. But really, was it enough for them to arrest me? Anyone could have done this.”

Once he was in custody, federal officials tried to improve the case against him, FBI documents and court records show. Search warrants for Curtis’s Corinth, Miss., home and his car were obtained the day after he was arrested. Four days after his jailing, warrants were obtained for his Tom-Tom Global Positioning System device and cellphone, records show.

Criminal justice experts say the arrest of Curtis without any physical evidence to tie him to the crime harks back to the investigation of bioweapons expert Steven J. Hatfill, who was falsely accused of the 2001 anthrax-letter attacksthat killed five people. Like Curtis, Hatfill had an unpublished novel that seemed to tie him to the crime.

With Curtis, however, experts said the FBI’s leap was larger.

“Hatfill had technical qualifications and a background that also led the FBI to zero in on him, but this guy is an Elvis impersonator with an apparent history of mental instability and a Facebook page with some distinctive and curious language on it,” said Amy E. Smithson, a senior fellow with the James Martin Center for Nonproliferation Studies who studies biological weapons.

Neilson, Curtis’s attorney, said he understands why the FBI and other federal authorities — including the Capitol Police, the Secret Service and the Department of Homeland Security — focused on his client. But Neilson said they crossed the line when they shackled his hands and feet and arrested him before they searched his home and car.

“I was the FBI supervisor in this district for years. I’ve run plenty of investigations, and I can tell you this is not the way to run an investigation,” Neilson said. “I would not have arrested him based on stuff that I found off his Facebook page.”

He said Curtis should have been asked to accompany officials to a federal facility for questioning — without being arrested — while they secured a search warrant and conducted a search.

Andrew J. Scott, a retired Boca Raton, Fla., police chief and expert court witness on police procedure, said authorities had enough information to detain Curtis while the investigation proceeded, but probably not enough to arrest him.

“The letters and his mental state would not likely add up to probable cause, which you need to make an arrest,” said Scott, a graduate of the FBI National Academy. “The evidence came from publicly available social-media sites. And the last time I checked, psychological profiling is not an element of probable cause. Without further investigating, it can lead to the kind of fiasco we are seeing here.”

Criminal justice experts said the political pressure from Washington to solve the ricin case would have been intense, particularly since the president was targeted and it occurred around the same time as the Boston Marathon bombing. Some experts said the Sept. 11, 2001, attacks taught law enforcement officials to do everything possible to prevent attacks, even if it means arresting the wrong person.

“There would have been unlimited armchair quarterbacking if he was the guy and more letters went out while they continued to investigate him,” said Chris Swecker, who retired as chief of the FBI’s criminal division in 2006. “When the stakes are this high, they have a sense of urgency to move faster.”

Conflicting evidence

Even as federal investigators were asking for the psychiatric evaluation of Curtis and the continuance, they knew of evidence suggesting that Dutschke was behind the ricin-laced letters, according to an FBI affidavit unsealed Tuesday.

Curtis and Dutschke have a long-running dispute, and Curtis had accused Dutschke of trying to frame him in the ricin case.

Two days after Curtis was arrested, FBI agents found a witness who told them that Dutschke, a martial-arts instructor and former insurance salesman, had boasted about his ability to manufacture “poison.” He discussed placing it in envelopes and sending it to elected officials and said that “whoever opened the envelopes containing the poison would die,” the affidavit said.

On April 22, FBI agents watched Dutschke discard a coffee grinder, a dust mask and latex gloves in a trash bin. The dust mask tested positive for ricin, and an agent said that the coffee grinder could have been used to extract the poison from castor beans, the affidavit said.

Despite the evidence pointing to Dutschke, one day later federal prosecutors asked that Curtis be placed under house arrest.

“We said, ‘No way,’ ” Neilson recalled. “We were smelling victory at that point. We said, ‘Drop the charges and let him go.’ ”

Curtis’s attorneys sent a letter this week to the U.S. Attorney’s Office and the FBI asking them to pay for temporary housing for Curtis and compensate him for damage to his home. FBI agents who searched his house one day after his arrest destroyed framed artwork created by his children, dumped garbage on the floor and tore at least one door from its hinges, making the home uninhabitable, his attorneys said.

Even if the damage was unavoidable as a result of a thorough search, federal authorities are legally required to fully compensate Curtis, according to Scott, the former Boca Raton police chief.

“The proper thing to do, the first moment you realize you have the wrong guy, would be to send over repair people to fix the damage,” he said. “It’s a black eye for law enforcement to make a mistake like this and then to not try to immediately make it right.”

Alice Crites in Washington contributed to this report.

Discuss this topic and other political issues in the politics discussion forums.