JOLIET, Ill (AP) - The crime scene technician didn't think twice about the bottle of cleaning fluid near the bathroom where the body of Drew Peterson's ex-wife lay slumped in her bathtub - or whether it might have been used to wipe away evidence of a crime.
Six years later, as Peterson prepares to stand trial for murder in Kathleen Savio's death, the bottle underscores the huge challenge facing prosecutors: Before they ask jurors to convict Peterson of murder, they first must prove a homicide occurred in the first place.
Police were so sure Savio drowned accidentally that they didn't look twice at the cleaning fluid, and collected no forensic evidence. Even the coroner who conducted the autopsy in 2004 ruled the death an accident.
In most murder trials, the evidence of a slaying is as obvious as a bullet hole or a stab wound, and the only question is "whodunnit?" But in Peterson's case, nothing is obvious.
"This is a true circumstantial evidence case,"' said Vincent Bugliosi, who won a murder conviction of Charles Manson in the 1969 slayings of Sharon Tate and six others even though Manson was not at the scenes when the slayings occurred. "In circumstantial evidence cases you're putting one speck of evidence upon each other... You're putting on evidence showing the unlikelihood that this is an accidental death."
At a pretrial hearing to determine what hearsay - or secondhand - evidence a judge will allow a jury to hear at Peterson's trial, prosecutors have been trying to turn a bathroom into a crime scene. Defense attorneys say they'll call witnesses beginning Wednesday.
In a preview of what is sure to be repeated at Peterson's trial, prosecutors called witnesses to testify about Savio's medical history, her personal habits, even details about her house. They also questioned a pathologist who conducted a second autopsy on Savio's body, which was exhumed in 2007 after Peterson's fourth wife, Stacy Peterson, vanished.
Longtime pathologist Dr. Larry Blum, who ruled Savio's death a homicide, testified there were fresh bruises on her body that would not have come in a fall. And a gash on her head, which led investigators to the original conclusion that Savio slipped and fell, could have been made immediately after she died, he said.
Other witnesses talked about Peterson's training in subduing suspects, knowledge of choke holds and his background in martial arts - likely signaling that prosecutors will suggest the former Bolingbrook police officer overpowered Savio and put her in the tub.
Peterson's attorneys will try to convince a jury that Savio's medical problems could have caused her to fall.
Savio had a heart murmur, periodontal disease and cervical vertigo. Although her neurologist testified that in his 30 years of practice, he'd never seen that kind of vertigo cause anyone to fall, he acknowledged Savio's medical records show she complained of dizziness and numbness.
"That opens the door for a defense attorney to bring in almost anything, drug use, drinking, whether she walked in her sleep or had dizzy spells," said Terry Sullivan, a prominent Chicago attorney and former prosecutor.
Which might explain why prosecutors asked so many questions about Savio's bathroom.
Witnesses said there were no towels, no robe and no other clothes near the tub, and toiletry items lining the tub's edge were undisturbed. Prosecutors likely want jurors to believe if Savio was taking a bath, she'd at least have laid out a towel and if she did fall, she would have knocked something over.
Then there was Savio's hair. It was down when her body was found, but a woman who had lived with Savio said Savio always put her hair up in a clip before taking a bath.
Some of those answers will resonate with jurors, said Marilyn Brenneman, a prosecutor in Seattle's King County, who's handling a similar case in which a man was charged with killing his 3 1/2-year-old stepdaughter after the death was originally ruled an accident.
"Women on the jury will understand putting hair up because they don't want to have to dry it again," she said.
To argue that Savio's death was a homicide, prosecutors have to overcome something else: There is no evidence of a break-in, and no obvious explanation for how anyone could have gotten inside, killed Savio and gotten out without anyone noticing.
Witnesses included a man who now lives in Savio's house who recounted how was able to climb in a window after locking himself out. Peterson's second wife told of seeing Peterson with locksmith tools. And Peterson friend Rick Mims testified he once followed Savio to work at the request of Peterson, who'd told him he was going to sneak into Savio's house to retrieve "papers." When Savio left work, Mims said he alerted Peterson.
But nobody testified to actually seeing or hearing Peterson - or anyone else - sneak inside Savio's house.
That means the original challenge remains: overcoming a lack of physical evidence, like fingerprints or DNA, to prove she didn't just drown.
"You have to pile a lot of suspicious circumstances on top of each other," Bugliosi said. "You have to get to the point where you can say (to a jury) 'Come on folks."'