But both agree on this point: No one can say for certain whether the jury would have reached a different verdict if the evidence had not been overlooked.

Bringing the evidence to light

Repeated requests by WKMG beginning in 2009 for a copy of the hard drive that contained the Internet histories were denied by the state attorney's office, which claimed -- correctly, it turned out -- it did not have the data in its possession.

Sheriff's computer investigators copied the entire hard drive from the Anthony's HP desktop computer after seizing it in July 2008 and gave prosecutors vague analysis of its activity and fragments of a miniscule amount of the vast information on them. The sheriff turned over the original hard drive to the Baez team in 2008 after it had been copied, Baez said.

After Baez revealed the "foolproof suffocation" search in his book, Phoenix attorney Isabel Humphrey requested and received a copy of the browsers’ histories from the Sheriff's Office.

Baez's theory that George Anthony did the search while contemplating suicide "was as crazy as the nanny story," Humphrey told WKMG, referring to Casey Anthony's original claim that a babysitter had kidnapped Caylee.

She obtained the data in August and turned it over to John Goetz, a retired engineer and computer expert in Connecticut. The pair had become acquainted online while following and discussing the case through the amateur sleuthing web community, Webslueths.

Using free software available on the Internet since 2004, Goetz said it took him less than two hours to extract more than 35,000 records detailing the computer's online activities from 2004 until it was seized in July 2008.

"Once you have converted the Internet history records, it really doesn't take more than 15 to 20 minutes to look through the entire Internet history for June 16," said Humphrey. "And I would think if there was one day you would pick to look at, that would be the day."

Goetz and Humphrey homed in on June 16, 2008, and quickly discovered the misspelled search for "fool-proof suffication."

"It shows you a state of mind that was present on the actual afternoon it appears the child had died," Humphrey said. "So I think it would be important regardless of who it was making the searches, but in this case it's certainly important that it appears to be Casey Anthony herself."

What they found astounded them and left at least one crucial question unanswered: How could prosecutors have not used this at trial?

Searching for that answer, they turned the browser history files over to WKMG.

After authenticating the records and interviewing defense, prosecution and Sheriff’s Office sources, it became clear: two citizen-investigators accomplished in less than three hours what an army of Orange County investigators and prosecutors failed to do in three years: uncover in detail what Casey Anthony was doing online the day Caylee died.

Of course, unbeknownst to investigators and prosecutors, it was also uncovered many months earlier by someone else: Jose Baez.

The defense: George did it

"I don't understand how no one ever knew about this evidence," Baez told WKMG. "We were keeping it close to the vest and ready to counterpunch in the trial, and it never came out."

The defense's still-cocked counterpunch: George Anthony did it.

After Baez's computer expert found the June 16 search for “foolproof suffocation" (Baez said he cannot reveal exactly when that was), Baez said he suspected the state knew about it, too, and was going to surprise the defense with it at trial.

In his revealing book, "Presumed Guilty," Baez accused investigators of "pulling a fast one" by concealing the vast majority of the June 16 computer history from the defense. Mostly vague references to that day's activity and some images were included in the documents turned over to the defense by the state in the discovery process.