Andrea Yates, the Texas woman who drowned her five young children four years ago, will likely get a new trial, prosecutors said. But a plea deal "isn't an option," according to her defense attorney.

The Texas Court of Criminal Appeals on Wednesday declined to interfere with a lower court's decision to overturn her convictions, letting that decision stand. Yates had been convicted of murder in 2002, and the First Court of Appeals in Texas overturned the convictions in January after finding a key witness gave false testimony.

Harris County Assistant District Attorney Alan Curry said he would seek a new trial or consider a plea bargain — the latter option being highly unlikely.

"Andrea Yates knew precisely what she was doing," Curry said. "She knew that it was wrong."

Yates' attorney, George Parnham, told a press conference Wednesday that not a day goes by where his severely mentally ill client doesn't feel remorse about what she did to her children.

And in spite of prosecutors' talk of a plea deal, it isn't going to happen as far as Parnham is concerned.

"Obviously a plea bargain isn’t an option, as long as there's nothing on the table to address the mental health issues that are so apparent with Andrea," Parnham told reporters Wednesday afternoon. "Given that, the only other option is to go to trial. I don’t believe there will be any meaningful negotiations in this matter short of going before a jury."

Earlier Wednesday, he told FOX News his client was "back to square one," and a new trial would be something "she dreads extremely."

Yates' attorneys claimed in her 2002 trial that she suffered from mental illness, postpartum depression and postpartum psychosis. The jury agreed that Yates was mentally ill but decided she knew what she did was wrong, and found her guilty of two capital murder charges for the deaths of three of the children.

It is not unusual in multiple death cases to file charges for only some of the victims.

Curry said if the case goes back to trial, he is confident that Yates would be convicted again.

Parnham said because she was not sentenced to death in her first trial, it is highly improbable Curry will seek the death penalty this time around.

The convictions were tossed because renowned forensic psychiatrist Park Dietz erroneously hinted that Yates may have watched an episode of TV crime show "Law and Order," in which a mentally ill woman drowned her children and was found not guilty by reason of insanity.

Dietz was a technical consultant on the show. However, the episode in question never aired, the show's executive producer told one of Yates' attorneys.

The First Court of Appeals in Texas ruled there is "a reasonable likelihood that Dr. Dietz's false testimony could have affected the judgment of the jury."

But prosecutors said that whether the episode existed or not had no bearing on whether Yates knew right from wrong when she murdered her children.

"The incorrect testimony — you can say it was false because it was incorrect — it was a mistake that happened. There was no intent to deceive. The evidence was credible that she knew right from wrong," Joe Owmby, a prosecutor in Yates' original trial, told FOX News.

Five mental health experts testified that Yates 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.

While prosecutors agreed Yates was mentally ill, they argued that the illness was not severe enough to impede her ability to know right from wrong. Jurors agreed, and did not declare her legally insane.

Yates, 41, was sentenced to life in prison and is jailed at a psychiatric prison in East Texas.

In spite of the unlikelihood of a plea deal — in which Yates would plead guilty to the killings rather than not guilty by reason of insanity — there is one scenario that both the defense and the prosecution might agree to.

"The government would have to give up the ghost on seeking the death penalty, the sentence being life in an institution instead of in jail [with the rest of the prison population] without the possibility of parole," FOX News Senior Judicial Analyst Judge Andrew Napolitano told FOXNews.com. "That's the only guilty plea that would be acceptable."

Yates isn't currently housed with the general inmate population, and Napolitano said both sides would have to concur that she should spend the rest of her life in either a mental institution or a psychiatric prison without the chance of ever going free.

"The jury found that she is not a danger to anybody else, that she’s so crazy she couldn’t hurt a fly in jail," Napolitano told FOXNews.com.

But, he added, Texas prosecutors are elected, meaning they have to answer to voters.

"It's a rough-and-tumble, swaggering electorate who like to see the guilty punished to the max," Napolitano said. "I don't know that a plea deal is in the cards. It depends on the political wishes of the prosecutor."

Parnham said Wednesday that lawyers aren't permitted to say in court what the penalty is for someone like Yates if the verdict is not guilty by reason of insanity.

"We know practically speaking that she isn’t allowed to go home [and is] sent to a state mental facility for a long time," he told reporters. "We aren’t allowed to tell the jury that. We’re not allowed to inform the jury that Andrea Yates will not walk out of the courtroom and ride down the elevator."

The murders of the Yates children, the youngest a 6-month-old baby and the oldest a 7-year-old, horrified the country and became a high-profile instance of postpartum depression used in an insanity defense.

Yates' name has been frequently evoked in similar cases, most recently last month when a young mother dropped her three young children to their deaths in the San Francisco Bay.

On June 20, 2001, within hours of her husband leaving for work, Yates drowned their five children one by one: Noah, 7, John, 5, Paul, 3, Luke, 2, and 6-month-old Mary. She then called police to her Houston home, answered the door in wet clothes and told an officer what she had done.

She led the officer to a back bedroom where the four youngest children's lifeless bodies were laid out on a bed. Police later found Noah, floating face down with his arms outstretched in the tub's murky water.

Before the murders, Yates had tried to commit suicide at least twice. She suffered from severe postpartum depression and psychosis, and was admitted to a mental institution on previous occasions.

Testimony from her trial also revealed that she believed she was possessed by the devil and could only be set free of the demons and save her children by bringing about her own execution.

Parnham said that one positive to come out of the case was increased awareness.

"The public is much more aware of the reality of postpartum psychosis and postpartum depression," he told the news conference Wednesday.

Yates has caused no problems in prison, where she works on inventory and stocking items in the commissary, prison spokeswoman Michelle Lyons said.

FOX News' Jane Roh, Catherine Donaldson-Evans and The Associated Press contributed to this report.