(CBS/AP) OXFORD, Miss. - The man charged with mailing ricin-laced letters to President Obama and a Mississippi senator was expected back in court Monday, and the hearing could reveal what evidence authorities have collected from searches of his home and vehicle.
Through his lawyer, Paul Kevin Curtis has denied any involvement in the letters sent to President Obama and Mississippi Sen. Roger Wicker (R-Miss.), as well as a third letter sent to a Lee County, Miss., judge.
A detention and preliminary hearing began Friday in U.S. District Court in Oxford, Miss., but was scheduled to continue Monday after it ran into the evening.
In the hearing, Curtis' lawyer, Christi McCoy, tried to show that authorities had collected little physical evidence.
FBI agent Brandon Grant testified late Friday that searches of Curtis' home and car had not been completed. He also said other tests, such as DNA analysis, were pending.
Prosecutors had wanted to delay the hearing, but McCoy objected, saying her client shouldn't have to stay in jail over the weekend if there wasn't enough evidence to hold him.
Curtis' attorney is likely to ask during Monday's hearing exactly what the searches uncovered over the weekend.
"He is adamant that he did not do this," McCoy said Friday.
She said her client has never been in possession of ricin and doesn't know how to make it.
"I have not seen anything to the contrary, so I have to accept what he is saying as the truth," McCoy said.
Grant testified Friday that authorities tried to track down the person who sent the letters by using a list of Wicker's constituents with the initials KC, the same initials in the letters. Grant said the list was whittled from thousands to about 100 when investigators isolated the ones who lived in an area that would have a Memphis, Tenn., postmark, including some places in north Mississippi. He said Wicker's staff recognized Curtis' name as someone who had written the senator before.
The letters also contained lines that were on Curtis' Facebook page, including the phrase, "I am KC and I approve this message," Grant said.
Grant also testified that there were indentations on the letters from where someone had written on another envelope that had been on top of them in a stack.
The indentations were analyzed under a light source and turned out to be for Curtis' former addresses in Booneville and Tupelo, though one of the addresses was spelled wrong, Grant said.
McCoy said the evidence linking the 45-year-old to the crime has hinged on his writings posted online, which were accessible to anyone.
So far, Curtis is the primary focus for investigators and the only person arrested in connection with the letters, but Grant testified Friday that authorities were still trying to determine whether there were any co-conspirators.
Family and acquaintances have described Curtis as a caring father and enthusiastic musician who impersonated Elvis and others, but struggled for years with mental illness.
Curtis' adult daughter, Madison Curtis, and brother Jack Curtis, both said after Friday's hearing that they'd never heard him criticize President Obama, though he was vocal in his feelings about many politicians.
His ex-wife, Laura Curtis, has said she does not believe he sent the letters.