CHARLOTTE (AP) — A mistrial has been declared in the case of three men accused of attacking NASCAR driver Mike Wallace and his daughter after a June concert in Charlotte, North Carolina.

Local news outlets report that Judge Ronald Chapman declared the mistrial Wednesday after learning two potential witnesses were in the courtroom when the case started. Judges and attorneys don’t want witnesses to hear anything that might influence their testimony.

A spokeswoman for the Mecklenburg County District Attorney’s Office said prosecutors will retry the case.

The two potential witnesses have been charged with contempt of court and will go before the judge next month. The judge had warned all potential witnesses to stay out of the courtroom.

Wallace and his daughter Lindsey were hospitalized after a fight following the June 17 Rascal Flatts concert.