Shannon Guess Richardson, 35, appeared in a Texarkana courtroom after being charged with mailing a threatening communication to the president. The federal charge carries up to 10 years in prison, U.S. attorney's office spokeswoman Davilyn Walston said.
Richardson, a mother of five who has played bit roles in television shows, was arrested earlier Friday for allegedly mailing the ricin-laced letters last month to the White House, Bloomberg and the mayor's Washington gun-control group. The letters threatened violence against gun-control advocates, authorities said.
Her court-appointed attorney didn't immediately return a message seeking comment.
According to an FBI affidavit, Richardson contacted authorities on May 30 to implicate her husband. She later failed a polygraph test and investigators also found inconsistencies in her story, the document said. Richardson then admitted mailing the letters knowing they contained ricin, but said her husband had typed them and made her print and send them.
No charges have been filed against her husband, Nathaniel Richardson. His attorney said the couple was going through a divorce and that the 33-year-old Army veteran may have been set up by his wife.
FBI agents wearing hazardous material suits were seen going in and out of the Richardsons' house on Wednesday in nearby New Boston, about 150 miles northeast of Dallas near the Arkansas and Oklahoma borders. Officials have said the search was initiated after Richardson contacted the FBI and implicated her husband.
John Delk, who represents Nathaniel Richardson, told The Associated Press that his client was pleased with his wife's arrest and was working with authorities to prove his innocence. Delk said he wasn't anticipating that Nathanial Richardson would be arrested. "But until I'm sure they're not looking at him being involved, I can't say much more," he said.
Bloomberg issued a statement Friday thanking local and federal law enforcement agencies "for their outstanding work in apprehending a suspect," saying they worked collaboratively from the outset "and will continue to do so as the investigation continues."
Shannon Richardson's resume on the Internet movie database IMDb said she has had small television roles in "The Vampire Diaries" and "The Walking Dead." She had a minor role in the movie "The Blind Side" and appeared in an Avis commercial, according to the resume.
She was seen leaving a Texarkana hospital on Friday shortly before the court hearing, though it was unclear why she was there. A hospital spokeswoman didn't return a phone message seeking comment.
Delk said the Richardsons were expecting their first child in October. Shannon Richardson also has five children ranging in age from 4 to 19 from other relationships, four of whom had been living with the couple in the New Boston home, the attorney said.
The FBI is investigating at least three cases over the past two months in which ricin was mailed to Obama and other public figures. Ricin has been sent to officials sporadically over the years, but experts say that there seems to be a recent uptick and that copycat attacks made possible by the relative ease of extracting the poison may be the reason.
If inhaled, ricin can cause respiratory failure, among other symptoms. If swallowed, it can shut down the liver and other organs, resulting in death. The amount of ricin that can fit on the head of a pin is said to be enough to kill an adult if properly prepared. No antidote is available, though researchers are trying to develop one.
Danny Robbins reported from Dallas. Associated Press writer Adam Goldman contributed to this report from Washington.