Peterson was on hand as prosecutors and his defense attorneys argued over the major piece of evidence.
Prosecutors are calling it the murder weapon - they went to court to ask the judge to allow the jury to see Kathleen Savio's bathtub. Savio, the former Bolingbrook cop's third wife, was found dead in the dry tub in 2004 in her Bolingbrook home.
The defense says Savio drowned after she slipped and fell, while the state claims Peterson killed Savio in the tub and staged it as an accident.
Will County Assistant State's Attorney John Connor argued that it is important for the jury to actually touch and see the size of the tub.
"The problem with the tub is you're only giving the jurors a partial view of what bathroom actually looked like, and if you listen to my argument, and if you look at the photographs, you'll see there's a wall, there's a stained glass window, there's various items there that she could have tripped over," said Peterson's attorney, Joe Lopez.
Lopez also argued the tub would only be brought into the courtroom for dramatic effect. The judge sided with the defense and will not let the jury see the tub. However, the judge did not close the door on the subject.
"The judge has left the door open if the tub is reinstalled to a potential visit by jury," said Will County State's Attorney James Glasgow.
"I wouldn't support that, because I don't think the government should be marching into people's homes reinstalling fixtures that they have out," said Lopez.
While Judge Edward Burmilla ruled with the defense on the bathtub motion, he struck down their request in another effort to have some hearsay testimony concerning statements from Kathleen Savio banned from the trial.
"Judge Burmilla's rulings are thoughtful and well-reasoned and he's doing everything that he needs to do to make sure that the evidence comes in in a lawful way and that this defendant will get a fair trial," said Glasgow.
Prosecutors also filed a motion to allow the testimony of an expert in aquatic accidental deaths.
The expert would talk about how rare it is for a healthy person to die from slipping and falling in a bathtub. Because of the late filing, the judge ruled he will not allow the expert's testimony in the trial.
Jury selection is scheduled to begin July 23, with opening statements the following week.