DURHAM, N.C. — "They say it's an accident that was caused by a couple of falls in the stairway. We say it is not. We say it is murder, and you'll have to decide." — Prosecutor Jim Hardin Jr. in his July 1, 2003, opening statement.

So did they prove it? Did prosecutors prove that Kathleen Peterson did not fall down a flight of stairs but was instead beaten to death by her husband, novelist Michael Peterson?

Jurors might not get to deliberate the 59-year-old defendant's fate for a few more weeks, but now that prosecutors Jim Hardin Jr. and Freda Black have rested their case, observers are picking over every bit of evidence to weigh it all against the heavy burden of proof beyond reasonable doubt.

During a 10-week presentation that at times seemed endless, prosecutors called 50 witnesses and presented hundreds of photos, documents, diagrams and other exhibits.

They presented evidence that, despite income from Kathleen Peterson's $145,000 a year job and a few other sources, the Petersons were spending more than they made, and were increasingly fearful that Kathleen might lose her job at Nortel Networks in the wake of her company's financial woes.

Michael Peterson surely knew that his wife had a $1.4 million life insurance policy and another $400,000 in cash assets. Prosecutors brought out these financial facts early in their case to suggest a motive for killing his wife on Dec. 9, 2001, with a blunt object and then staging the scene to look like a staircase fall before calling 911.

If the scenario seems farfetched even for a fiction writer like Peterson, prosecutors say he had the perfect model: the 1985 staircase death of a neighbor in Germany, Elizabeth Ratliff.

Michael and Kathleen Peterson dance at their wedding.

Hardin did not mention Ratliff during his opening statement back on July 1, but during hearings to have the Ratliff evidence admitted, the state suggested several theories: Peterson either killed Ratliff too, or at least knew what a fall down stairs looked like from having seen his friend's body. He also would have observed how German and U.S. military investigators wrote the death off as an accident.

The prosecution isn't only relying on evidence of the other death to bolster their first-degree murder case. Indeed, some observers were surprised that the judge allowed testimony about Ratliff's death.

The state first presented a blood spatter expert who concluded that stains in the stairwell indicated that Kathleen Peterson was struck at least four times and that Michael Peterson's khaki shorts and sneakers — presumably while he was wearing them — were in the stairwell when something bloody was hit with enough force to create the smallest of spatter drops. 

Small droplets of blood were deposited inside Peterson's shorts.

But the prosecution saved its most powerful testimony for last. Dr. Deborah Radisch, the North Carolina pathologist who performed the 2001 autopsy on Kathleen Peterson's body and a second autopsy on the exhumed body of Elizabeth Ratliff just a few months ago, testified about the many similarities between the deaths.

Radisch's conclusions couldn't be plainer. She believes, based on her experience and training, that Kathleen Peterson was beaten to death with a blunt object and that her wounds were too numerous to be explained by a fall. She also described defensive wounds on her hands and broken cartilage in her throat that pointed to a strangulation attempt. 

The defense is expected to call witnesses who will say Peterson idolized his wife, treated her well and that the couple never fought, at least not in front of others.

But prosecutors have already countered the defense portrayal of the Petersons' marriage as a "storybook" romance with testimony of a former male prostitute Peterson corresponded with online and even tried to arrange a meeting with. The state also entered into evidence e-mails in which Peterson, or someone using his e-mail account, discussed all sorts of homosexual acts he liked and didn't like.

Former male escort Brent Wolgamott testified about his correspondence with Michael Peterson.

Judge Orlando Hudson Jr. gave the prosecution wide latitude to present virtually everything lawyers for the People of North Carolina wanted. Indeed, some of Hudson's rulings, such as allowing the Ratliff evidence, may provide the defense good cards to play on appeal in the event that Peterson is convicted.

Although the Ratliff evidence may tend to help the prosecution's effort, the defense believes that it could confuse some jurors or cause others to question why prosecutors felt compelled to literally dig up a 1985 death. The defense will argue during final summations that very little investigative work was done by police concerning Ratliff's death, which detectives knew about early on, until just before jury selection began.

And by putting on the Ratliff evidence prosecutors ran another risk: their medical experts testified that they disagree with the findings of a U.S. Army pathologist and a distinguished pathology institute that Elizabeth Ratliff died of natural causes. If jurors become confused about which experts to believe and which ones to disregard, the case could turn out to be the "battle of experts" defense lawyer David Rudolf promised the jury the case would be from the start.

Prosecutors have already been led astray by one expert.

During his opening statement, Hardin told jurors he would present evidence that the hard drive in the computer found in Michael Peterson's study was wiped clean of everything the day after his wife's death and then someone reinstalled only select programs. But during testimony, the prosecution expert who led Hardin to promise that evidence was forced to admit that he had learned only after the trial started that the computer's anti-virus software automatically performed a function that only made it look like someone had tried to sanitize Peterson's hard drive. 

Whether jurors will look upon the incident as an indication that the prosecution is sloppy and unreliable is one of the many unknowns midway through the proceedings.

What motive jurors might believe Peterson had for killing his wife is also up for grabs. Will they find that financial stress in the Peterson household was too much for the writer, who had not earned any significant income in 2001? Or will they discard the monetary motive since Michael Peterson learned shortly before his wife death that one of his novels had been optioned for a movie?

Will they conclude that Kathleen Peterson found out about her husband's interest in homosexual pornography and e-mail exchanges with a male prostitute?  Or will they determine that there was no evidence that his wife even knew about Michael Peterson's bisexuality?

Moreover, can the defense overcome the strongly held opinions of the blood spatter expert and pathologist who performed the autopsy?

At the end of the prosecution's case, many questions remain, and the defense's case will surely raise more.

But in the final reckoning, the only answer that matters is the one the jury must answer: Guilty or not guilty?