By taking the extraordinary step of putting the officials on the stand who were involved in the badly botched initial investigation, prosecutors sought to explain to jurors why they have no physical evidence linking Peterson to the alleged murder of Kathleen Savio inside her suburban Chicago home in 2004.
Peterson, 58, was only charged after his fourth wife, Stacy Peterson, went missing three years later. Savio's body was exhumed then and her death reclassified from an accident to a homicide. Peterson has pleaded not guilty to first-degree murder.
Deputy Coroner Michael VanOver said investigators concluded Savio's death was accidental while her corpse was still sprawled in the dry bathtub - her hair soaked with blood. As he examined her body and inquired if he should take measures to preserve potential evidence, others indicated there was no need.
"I asked ... if they thought there was something wrong here, and they stated, 'No,'" VanOver recalled.
Dressed in a pinstripe suit, Peterson rested his hand on his cheek as he followed the testimony in the Joliet courtroom. When a photograph of Savio's body was displayed, he showed no visible emotion.
Another witness, crime-scene investigator Robert Deel, told jurors he saw no signs of a struggle at Savio's home. At other murder scenes, he has seen doors broken off their hinges, holes punched into walls and blood everywhere.
"When someone is fighting for their lives, it's an intense thing," he added dramatically. He also said there were no signs that an injured Savio or her bloodied body had been dragged across the floor.
Deel conceded he did only a cursory search of Savio's home and that he didn't bother going into some rooms. Asked about a half-full glass of orange juice in the kitchen, he said it was never tested for fingerprints, blood or anything else. He also didn't notice a deep, 2-inch-long gash on the back of her head.
A prosecutor repeatedly tried to suggest Deel and other investigators might have destroyed evidence, even questioning how they lifted Savio's body from her large, circular bathtub. Deel sounded irritated.
"It's not a graceful or pretty site," he said about removing her body. "We just got her out of there. ... She flops over the side."
He appeared cowed at times as prosecutors pressed him to acknowledge the investigation should have been more thorough. But later, he appeared more defiant and confident, defending his work at the scene.
"Is it still your opinion that Kathleen Savio died in an accident, is that correct?" defense attorney Joel Brodsky asked during cross-examination.
"Yes," Deel said firmly.
Typically, it is prosecutors who herald the work of investigators at murder trials. But the Peterson prosecutors are working to show the investigation was shoddy as a way to justify the heavily reliance on circumstantial and normally prohibited hearsay evidence.
For their part, Peterson's attorneys endeavored to defend the investigation as perfectly adequate, suggesting the reason there is no physical evidence is because there was no crime.
VanOver, the deputy coroner, insisted he had suspicions from the start.
He said a lack of soap scum along the inside of the bathtub was one reason why. He also said the position of the body in the tub didn't suggest Savio had fallen and bottles lined along the tub had not toppled over, which he said he would have been expected if someone had taken a fatal fall.
But he acknowledged under cross-examination that he didn't express his concerns to investigators.
"You didn't tell anyone you thought it was a homicide, right?" defense attorney Darryl Goldberg asked.
"No, I did not," VanOver said flatly.
Out of earshot of jurors, defense attorney Steve Greenberg complained that prosecutors were trying to send a message to jurors that, if only investigators had done a better job, they would have found evidence proving his client committed murder.
"But their (investigators') failure to find something doesn't lead to the conclusion ... that Mr. Peterson committed a crime," Greenberg said.
He later added that prosecutors "can't try to convict someone by showing evidence that's not there. ... It's totally inappropriate."
Judge Edward Burmila declined to bar prosecutors from dwelling on the shoddy investigation. But he said he would not let them suggest to jurors during testimony or in their closing arguments that there must have been evidence in Savio's house that wasn't collected but that would have proven Peterson's guilt.
"If the state thinks they're going to argue that ... if (investigators) looked closer, they would have found Mr. Peterson's fingerprints (or other evidence proving he killed Savio), that's not going to happen," he said.