Vaughn is accused of murdering his wife and their three children inside the family's SUV.
Sergeant Robert Deel, an Illinois state trooper, described the scene investigators found after the fatal shootings. Jurors reviewed dozens of pieces of gruesome evidence collected by Sergeant Deel.
Deel was the lead crime scene investigator called to the murder investigation of Kimberly Vaughn and her three children in Channahon in 2007.
Christopher Vaughn was also shot in the arm and leg that day. He alleges that Kimberly Vaughn did the shooting. But Christopher Vaughn has been charged with the murders.
Prosecutors are building a case against Christopher Vaughn in the fifth day of his trial.
The judge's ruling limited what Sergeant Deel could be asked on the witness stand.
Much of his testimony confirmed he found photos of the car, gunshot wounds and actual evidence at the scene.
Under cross examination, Sergeant Deel testified that the vehicle was towed with the bodies still inside and that was unusual. He also testified that a towel from the scene had been washed without testing whose blood was on it.
"Whether that is her blood on the towel or someone else's could be important information," said Deel testified.
Vaughn's attorney George Lenard also asked Deel about blood on Kimberly that was never tested. Lenard asked, "you don't know if any of the children's blood is on Kimberly's arm or hand?" Deel responded, "correct."
In the Drew Peterson case, Deel was criticized for how he handled the murder scene of Kathleen Savio which was initially ruled as accidental. The jurors in the Vaughn case didn't hear anything about that due to a judge's ruling.
Next week, prosecutors will next show the jurors the videotaped statement that Christopher Vaughn made after the murders. Prosecutors expect to call witnesses for the next week and a half or two weeks and then attorneys for Vaughn will have their opportunity to call witnesses in Mr. Vaughn's defense.