A man who was to be tried for assault smacked his court-appointed lawyer during jury selection, stunning the potential jurors and forcing the judge to declare a mistrial.

Justin Jacobson, 21, and his lawyer W. Larry Jefferson had been whispering back and forth during proceedings Wednesday in Thurston County Superior Court, witnesses said.

Jacobson, whose eyes were focused elsewhere, backhanded his attorney without warning, said Undersheriff Neil McClanahan, who was in the courtroom because he had received a summons for jury duty in the case.

"Not only did you see it, you heard it," McClanahan said.

Guards immediately subdued Jacobson, and Judge Paula Casey declared a mistrial because the incident was witnessed by the prospective jurors.

"I'm just shaken up. It's not something you expect when you're working," said Jefferson, who was treated for a bruised sternum at Providence St. Peter Hospital. He withdrew from the case.

The case against Jacobson stems from a reported attack on two guards while he was incarcerated at Maple Lane School, a state institution for juvenile delinquents.