WASHINGTON - The question of Hamlet's sanity remains unanswered after a Washington jury delivered an evenly split verdict on whether he should be held criminally responsible for the fatal stabbing of Polonius.

Wearing a brown jail suit with a white ruffle collar, "Hamlet'" appeared Thursday before Supreme Court Justice Anthony Kennedy in a sold-out theatre at the John F. Kennedy Center for the Performing Arts. The unscripted mock court trial, combining modern law and Shakespeare's account of Hamlet, was part of the ongoing Shakespeare in Washington festival, which runs through June.

After the verdict, Kennedy remanded the Danish prince to "the pages of our literary heritage."

In Shakespeare's play, the killing of Polonius occurs shortly after Hamlet returns to Denmark for the funeral of his father, the king of Denmark. A grieving Hamlet learns that his mother has married his uncle Claudius, the new king. A ghost tells Hamlet that Claudius murdered his father, and an enraged Hamlet vows revenge.

But Hamlet's plans go awry. He stabs Polonius, the councillor to the king, after hearing a noise behind a curtain and mistakenly thinking it is Claudius eavesdropping.

The split verdict by the 12 jurors, who were selected beforehand and deliberated for about 20 minutes, was a major blow for the four lawyers who argued the case.

"No Dane is above the law," San Francisco attorney Miles Ehrlich said in opening statements. "When you pick and choose your time to kill, you are in control."

In arguing that Hamlet was not insane, Ehrlich noted that Hamlet plotted to kill Claudius and nearly did so in a chapel while Claudius was praying. Hamlet decided to wait because he didn't want to send Claudius to heaven.

Alan Stone, a Harvard University professor of law and psychiatry, testified for the prosecution that Hamlet did not have a clear mental illness. Thousands of people have studied Hamlet's thoughts, the former president of the American Psychiatric Association said, "not because he was a madman but because he was brilliant."

Hamlet's vision of a ghost was not delusional, he argued, but was likely normal for his culture. He said Hamlet was plotting to kill.

"Many of his puns are filled with anger and rage,'' Stone said. "He seems to think there is an audience.''

In a heated exchange with Stone, Hamlet's attorneys argued that Hamlet, who sat silently through the proceedings and refused to take the stand in his own defence, showed clear signs of insanity.

"He talks to himself a lot, like a crazy person,'' said lawyer Abbe Lowell, whose clients have included convicted former GOP lobbyist Jack Abramoff. "What about the soliloquies and the asides?"

But Stone rejected Lowell's claim that Hamlet's words, such as "To be or not to be?" were signs of a "suicidal funk."

Columbia University psychiatry professor Jeffrey Lieberman, testifying for the defence, said Hamlet's question "To be or not to be?" was one of history's best examples of ambivalence -- a cardinal symptom of psychosis.

Lieberman said the voices Hamlet heard while suffering hallucinations were "as real as your voice is being perceived by me."

Kennedy conceived the production for the fourth time. Prior juries in Boston, Chicago and Washington have found Hamlet sane. The show was hosted by Michael Kahn, artistic director of Washington's Shakespeare Theatre Company.