Murder trial of Drew Peterson to begin

• Kathleen Savio was found dead in her bathtub in 2004
• First called an accident, her death was later ruled "homicide staged to look like an accident"
• Her ex-husband, Drew Peterson, was charged in 2009 and held on $20 million bond
• He is also the prime suspect in the 2007 disappearance of his fourth wife, Stacy Peterson

(CNN) -- Eight and a half years after his third wife was found dead in a bathtub, the murder trial of former Chicago-area police officer Drew Peterson is set to begin in earnest with opening statements Tuesday.

The 58-year-old Peterson is accused in the 2004 death of his third wife, Kathleen Savio, in a trial that has been postponed for two years. He also remains under investigation in the October 2007 disappearance of his fourth wife, Stacy Peterson.

A jury of seven men and five women -- chosen over two days last week -- will weigh Drew Peterson's fate during a trial in Joliet, Illinois, that is expected to be last about a month according to his lawyer, Joel Brodsky.

After the jury selection was finished Tuesday, Will County, Illinois, State's Attorney James Glasgow told reporters, "We're ready to go... We're anxious to get to trial, put the evidence before the jury and arrive at a verdict."

Brodsky, meanwhile, said he planned to use his opening statement to "tell the story of Drew Peterson from beginning to end ... and show the state's theory is implausible at best."

Peterson was married to Savio in 2001 when he met then 17-year-old Stacy Kales (who later became Stacy Peterson), and those two began having an affair. Savio and Peterson filed for divorce from each other that October, and their relationship remained contentious for the next several years.

Boilingbrook, Illinois, police records indicate officers were called to Savio's home 18 times to intervene in domestic fights from 2002 to 2004. Drew Peterson had Savio arrested twice for domestic violence, though she was found not guilty in both cases.

A judge in March 2002 granted Savio a protection order from her ex-husband, prohibiting him from being near her, entering her home and taking out their children except for two brief weekly visits. (Their two sons later spent every other weekend with their father, per the divorce settlement.) Savio had claimed that, months later, Peterson held a knife to her throat and threatened to kill her inside her home.

In October 2003, three months after giving birth to what was Peterson's fifth child, the then 19-year-old Stacy Kales and 49-year-old Drew Peterson married. The Will County prosecutor alleged that, later that year, Peterson tried to pay someone $25,000 to kill Savio. And her sister Sue Doman told ABC News years later that Savio had called her saying she feared "he was going to kill her, and it was going to look like an accident."

Drew Peterson picked up his two sons from Savio's home on February 27, 2004, spending the next two days with them. Prosecutors believe that he entered her home again early on February 29 and killed her; she was found naked and dead in her dry tub the next day. At the time of her death, a court was mulling how their marital assets would be divided and Savio was set to receive part of Peterson's pension and other support.

Police initially treated the scene as an accident, although the Illinois State Police was later brought in to investigate. On March 20, Dr. Bryan Mitchell from the Will County coroner's office said in an autopsy report that the cause of Savio's death was drowning, her hair was soaked in blood from a cut on her scalp, and she had small bruises on her body.

A six-person coroner's jury ruled her death an accident in May 2004, after an Illinois State Police officer told them investigators had no reason to suspect homicide and that the cut on her head was caused by a fall. This trooper hadn't gone to the death scene or to the autopsy, nor had he interviewed Peterson. Savio's family also testified in that coroner's jury hearing that Savio feared her ex-husband, who stood to benefit financially from her death.

Meanwhile, in October 2007, Stacy Peterson contacted a local attorney and told him she wanted to discuss filing for divorce. Later that month, after divulging her intentions to her husband, she disappeared. Drew Peterson said she abandoned her two children, ages 4 and 2, and ran off with another man.

The next month, state police labeled Drew Peterson a suspect in his fourth wife's disappearance, though neither he nor anyone else has been charged in that case. Stacy Peterson has never been found.

The investigation into Stacy Peterson's disappearance brought renewed interest in Savio's death. Authorities exhumed Savio's body, further tests were conducted, and her death was later ruled a "homicide staged to look like an accident."

In May 2009, months after a judge admitted authorities had an "extensive" collection of secretly recorded conversations with Peterson, Drew Peterson was indicted and arrested on murder charges in connection with Savio's death. He was ordered held on $20 million bond.

Brodsky, his lawyer, said then in a written statement that prosecutors would not be able to prove their case because "he didn't do it."

"There is no evidence that links Drew Peterson to the death of Kathleen Savio or anyone else for that matter," Brodsky said. "Drew did not harm Kathleen; he has said so from Day One. We're obviously disappointed a grand jury indicted him. But an indictment does not mean guilt."

Brodsky told CNN he believes the case has always been about circumstantial evidence and that he will bring a pathologist to trial who will say Savio died from an accidental drowning.

"I think the jury's going to see that, in fact, this always has been an accidental death and still is an accidental death," Brodsky

Martin Glink, an attorney for the Savio family, said relatives were glad the grand jury felt there was enough evidence to charge Peterson.

"We're very happy that the wheels of justice have continued to move, and they are pointing in his direction," Glink told CNN affiliate WLS-TV.

Peterson's trial had been set to start in July 2010, but was delayed. This past April, an Illinois appellate court ruled that prosecutors may use potentially incriminating statements made by Savio and Drew Peterson's still-missing-wife Stacy against him -- a key development in the case.

The ruling overturned an earlier judge's decision that forbid prosecutors from using eight statements made by Savio before her death and by Stacy Peterson before her disappearance. The defense had argued that using their statement violates Drew Peterson's right to confront the witnesses against him.