Casey Anthony In an April 5, 2011, email to sheriff's computer examiner Sandra Osborne, Burdick wrote, "I believe, based on your reports, that we can disprove” Casey Anthony’s claim that she was awakened by her father when Caylee disappeared. They could do that, Burdick wrote, “by demonstrating (if possible) what was actually happening (I guess that means user activity and Internet history) on the computer during the time frame."

In response, lead sheriff's Investigator Yuri Melich sent Burdick a spreadsheet that, our investigation found, contained less than 2 percent of the computer’s Internet activity that day.

Melich and Osborne relied on Internet data from the computer’s Internet Explorer browser – one Casey Anthony apparently stopped using months earlier. Since March, she preferred the computer’s Mozilla Firefox browser, as investigators already knew.

The spreadsheet sent to Burdick included 17 vague entries from the Internet Explorer browser history on June 16, 2008, and failed to list 1,247 entries recorded on the Mozilla Firefox browser that day -- including the search for “foolproof suffocation.”

The mistake meant prosecutors went to trial unaware of 98.7 percent of the browser history records created that day.

Even the scant data the Sheriff's Office did manage to find showed computer activity inconsistent with the claim that Casey Anthony was awakened that morning to learn her daughter was missing and then drowned.

In his powerful opening statement, Baez described the resulting scene between father and daughter, after Caylee's wet, limp body was recovered.

"He immediately began to yell at (Casey). Look what you've done! Your mother will never forgive you and you will go to jail for child neglect for the rest of your fricking life."

So, the jury was told, George Anthony disposed of the body and both he and Casey re-launched their lives in a secretly shared compact of denial and deceit.

"This is strange," Baez told jurors. "This is bizarre. This is the life of Casey Anthony."

No, prosecutors countered, this was about the murder of Caylee Anthony – one accomplished, they claimed, with poison, suffocation and plastic bags.

Had Casey Anthony testified, as Burdick said she expected she would, prosecutors wanted to use the browser information to impeach her. But Casey Anthony never took the stand and the state did not elicit from any other witness even the skeletal browser evidence it did have.

Melich's spreadsheet does show activity from Casey Anthony's password-protected account beginning at 7:52 a.m., indicating that she was on MySpace and researching sexy costumes for "shot girls" to wear at her then-boyfriend's nightclub events.

But none of the 1,247 overlooked Firefox browser actions that day -- including the potentially incriminating search that afternoon -- appear in the easily extractable Explorer browser files that Melich relied upon for his timeline.

Investigators knew Casey Anthony preferred the family computer's Mozilla Firefox browser, but they previously had trouble decoding it, sheriff’s officials said.

In 2008, in a deleted section of Firefox browser records, they found searches from March 2008 for "how to make chloroform,” “neck breaking,” “death” and other terms after they requested that Osborn search the hard drive for the word “chloroform.” That request came after the Sheriff’s Office found traces of chloroform in the trunk where, they claimed, Casey Anthony hid her daughter's body.

But when Melich assembled his 114-line spreadsheet in 2011, he transferred data from the Internet Explorer browser that Casey Anthony rarely, if ever, used after March 6, 2008.

Melich and Osborne declined comment, and the then-head of the computer crimes section, Sgt. Kevin Stenger, has retired and could not be reached for comment.

But in a Sept. 6, 2012, email exchange with a Phoenix attorney who obtained the browser histories in August through a public records request, Osborne offered this explanation for the oversight: "I have a very good reason why (the foolproof suffocation search) wasn't brought up during trial. I was never asked to conduct a search for 'suffocation' and the word does not appear in the Internet artifacts we prepared for trial, unfortunately."

In a statement to WKMG on Monday, the Sheriff's Office stood by Osborne and echoed her defense: “The Firefox record which contains the Google search for ‘suffication’ was neither extracted nor examined. A search for the keyword ‘suffocation’ was never requested from any OCSO investigator or the prosecutor’s office at any time during the investigation; therefore, this Internet record was inadvertently not discovered by Detective Osborne. … The agency has confidence in her knowledge and expertise in this very complicated field of computer forensics.”
When it comes to blame, the prosecution notes it requested the information from the Sheriff’s Office; the Sheriff’s Office states it was never asked to search for “suffocation.”