Christopher Vaughn is accused of murdering his wife and children with a shotgun on the side of the road in 2007.
The legal drama builds this week at the Will County Courthouse as two high-profile murder cases are tried in courtrooms next to each other.
Former Bolingbrook police sergeant Drew Peterson's trial enters its third week on Tuesday, and jury selection began Monday in the trial of Christopher Vaughn. In both cases the husbands are accused of murdering their wives.
Peterson is accused of killing his third wife, Kathleen Savio, whose body was found in a bathtub in her Bolingbrook home in 2004. Vaughn is accused of shooting to death his wife and children with a shotgun on the side of the road in 2007.
Prosecutors say Vaughn murdered his wife and three children, ages 12, 11 and 8, while the family was on their way to a water park. They were traveling near Channahon on I-55 when prosecutors say Vaughn pulled over and shot his family.
Vaughn had minor gunshot wounds to his wrist and leg, and told police he remembers his wife pointing a gun at him.
A controversial state police crime scene technician worked both the Peterson and Vaughn family cases. The technician, Robert Deel, reportedly initially thought it was Kimberly Vaughn who shot at her husband before killing her children and herself.
That is the argument Christopher Vaughn's defense attorneys are likely to make.
Kimberly Vaughn was taking the anti-seizure drug Topomax at the time of her death, which causes side effects including suicidal thoughts, Christopher Vaughn's attorneys argue.
A questionnaire released Monday asked jurors if they took prescription drugs, including Topomax.
In the courtroom, Vaughn introduced himself to the jurors, wearing a new haircut and a tan sport coat.
Questioning of the jurors gave some indication of how the trial might go. It is likely prosecutors will argue Vaughn did not do enough to protect his children.
Prosecutor John Long asked some of the potential jurors if they would go so far as to risk their lives if their children were in harm's way. Defense attorneys later objected to that line of questioning, arguing the prosecution was "trying to indoctrinate the jury to the state's theory of the trial."
Judge Daniel Rozak agreed to limit the questioning, warning prosecutors they were "getting dangerously close to crossing the line."
In the Peterson case, Deel, who was on the scene when Savio's body was found, originally thought Savio's murder was an accident. It later was ruled a homicide.
Deel already took the stand in the Peterson trial and has been criticized by prosecutors for failing to process Savio's bathroom as a crime scene after her body was found.
Peterson's trial resumes Tuesday. Vaughn's trial is expected to begin next Monday, Aug. 20.