The mother whose convictions in her children's drownings were tossed over false witness testimony is unlikely to see freedom soon, her lawyers said. The expert witness, meanwhile, said Friday he made an honest mistake and contended he got the erroneous information during a "passing conversation" with prosecutors.

Defense attorney George Parnham (search) said he had no plans to seek Andrea Yates' (search) release from the state prison where she works in the flower garden and has janitorial duties.

"A verdict of this magnitude does not mean that Andrea goes free," Parnham said.

A state appeals court on Thursday determined that the false testimony from forensic psychiatrist Park Dietz (search) led to her improper conviction in three of the five children's drownings in 2001.

During trial, Dietz, a consultant for the television program "Law & Order," described what he said was a show about a woman found innocent by reason of insanity for drowning her children. The three-judge appellate panel said prosecutors "connected the dots" with that false testimony to convince jurors that Yates patterned her actions after the episode, which turned out not to exist.

Dietz told "Good Morning America" on Friday said he got confused because prosecutors had told him there was a "Law & Order" episode with that plot.

"I put that in my notes and must have remembered those notes," he said. He said the misinformation came in "a passing conversation with the D.A.'s office."

"I believed they thought I would check it out and determine if it was true," he said. He said he hadn't done so because he didn't think Yates had acted because of a TV show.

"She says in recorded statements, including my interviews, that as she killed her children, she knew that it was wrong to do it. She knew God would disapprove. And she knew society would disapprove," he said. "That's the evidence."

Dietz, according to the court ruling, acknowledged his errant testimony to lawyers before jurors moved on to sentencing. Defense lawyers at the time sought a mistrial, but the trial judge refused.

"We conclude that there is a reasonable likelihood that Dr. Dietz's false testimony could have affected the judgment of the jury," the court said. "We further conclude that Dr. Dietz's false testimony affected the substantial rights of appellant."

The judges absolved the prosecutors of wrongdoing.

Yates, now 40, had pleaded insanity after drowning her five children one by one, then calling police to her Houston home and showing them the bodies in June 2001.

Testimony at her trial showed Yates was overwhelmed by motherhood, considered herself a bad mother, had attempted suicide and had been hospitalized for depression.

Five mental health experts testified she did not know right from wrong or that she thought drowning her children was right. Dietz was the only mental health expert to testify for the prosecution and the only one who testified she knew right from wrong.

"His testimony was critical to establish the state's case," Judge Sam Nuchia wrote. "Although the record does not show that Dr. Dietz intentionally lied in his testimony, his false testimony undoubtedly gave greater weight to his opinion."

Parnham said Yates was "surprised and not unpleased" by the new ruling.

"She has lots and lots of questions about what the future holds," Parnham said. "I told her, in so many words, that we weren't able to necessarily answer those questions because many of the decisions relative to what happens to Andrea have yet to be made by the district attorney's office."

Prosecutors said they would seek a rehearing before the appeals court and, if necessary, move the case up the appellate ladder. Prosecutors could also pursue the deaths of her two other children.

"We're disappointed but not shocked," said Joe Owmby, the Harris County assistant district attorney who prosecuted Yates. "We will proceed from here."

Even if she's eventually found innocent by reason of insanity, Troy McKinney, who argued Yates' case before the appeals court, said she would remain under care and under court jurisdiction.

"This is not a get-out-of-jail-free card by any stretch of the imagination," he said.

In a televised interview, Yates' husband, Russell Yates (search), said, "I'm happy, happy for Andrea."

"I think she needs to be in a state mental hospital until she's well," he said. "Had she not been mentally ill, she never would've done what she did."