False testimony by Psychiatrist in Andrea Yates case.

As reported on ABC News

Before Andrea Yates was convicted of drowning her children, a high-profile psychiatrist told jurors he had been a consultant on an episode of Law & Order that was similar to the Yates case and had aired prior to the real-life crime. It turns out — no such episode ever aired.

A grand jury is investigating Dr. Park Dietz's testimony in the prosecution of Yates, who was convicted last year of capital murder in the drowning deaths of her five children in a Houston suburb. Dietz told jurors during Yates' trial that an episode of Law & Order focused on a mother who drowned her children and was acquitted with an insanity defense, had aired weeks before Yates killed her five children in the same manner.

Prosecutor Joe Owmby referenced the show in his closing arguments before Yates was convicted of capital murder on March 12, 2002.

[...]

The defense did not find out until two days after the guilty verdict that no such episode existed, or had aired. Dietz, whose final bill was close to $50,000 in the Yates case, informed the Harris County District Attorney's Office that he had been mistaken about the Law & Order episode, and did not think it played a role in the drowning of the Yates children. In response, defense attorneys and prosecutors wrote a statement about the error that was read to jurors before they decided on Yates' punishment.

The possible legal consequences of this psych screwup are not clear.