(ABC News) -- On the day 2-year-old Caylee Anthony disappeared, someone in her house used the computer to run suicide-related searches, on terms including "foolproof suffocation" and "venturing into the pro-suicide pit," according to Casey Anthony's defense attorney Jose Baez.
Baez described the "bombshell evidence" in his new book "Presumed Guilty, Casey Anthony: The Inside Story."
One year ago, on July 5, 2011, Anthony was acquitted of charges of first-degree murder, aggravated child abuse and aggravated manslaughter for the death of her 2-year-old daughter Caylee Anthony. She was convicted of lying to law enforcement.
In the book, Baez wrote that the suicide-related searches were done one hour after Casey Anthony's father George Anthony said that she had left the home. Casey Anthony's mother Cindy Anthony was not home at the time and her brother Lee Anthony no longer lived there.
Though Anthony home computer searches for "chloroform" were heavily scrutinized during the trial, Baez said the suicide-related searches one of his experts later discovered were never disclosed.
"I have a hard time believing that law enforcement wouldn't check the internet history of the day that the child went missing," Baez said on "Good Morning America" Thursday. "That would have been bombshell evidence in the trial if it had come out.
Baez concedes in the book that computer experts say it is very difficult to prove who was the person using a computer at any given time, but that one can speculate based on the type of searches made.
On the morning of June 16, 2008, computer records show that someone, presumably Casey Anthony, spent about two hours on Facebook, Myspace and "researching outfits worn by shot girls in clubs," Baez wrote. Anthony's boyfriend at the time was a club promoter and Anthony was helping him manage the shot girls, the women who walk around the club selling shots of liquor.
A few hours later, someone got on the computer and logged into an AOL Instant Messenger account. Baez said that George Anthony had an AIM account and that Casey Anthony did not.
"Then someone typed in 'foolproof suffocation.' It was misspelled, and George was a poor speller," Baez wrote. "Google automatically corrected the spelling, and the first link that was clicked was 'venturing into the pro-suicide pit.' It appeared that someone was thinking about killing himself."
At the time these searches were being made, phone records showed that Casey Anthony was on the phone with her friend Amy Huizenga, who did not recall anything strange about the phone call, according to Baez.
"By looking at the websites being researched, all concerned with suicide and death, it certainly appears that the one who felt the blame was a guilt-ridden George Anthony," Baez wrote in the book. "It had to have been George on the computer because he said Casey was gone, and he was the only one out there trying to kill himself."
George Anthony attempted suicide in January 2009.
Police found him despondent and possibly under the influence of medication and alcohol in a Daytona Beach, Fla., hotel. Police also discovered a five-page suicide note in the hotel that Anthony had apparently written.
In the book, Baez also wrote that Casey Anthony has "serious mental health issues" and described her as someone "not playing with a full deck."
In early 2009, Baez wrote that Anthony finally told him her version of what happened the day Caylee died. She recounted waking up, Caylee being missing, searching for Caylee outside and finally seeing her father carrying Caylee's wet, lifeless body from the pool.
Anthony claimed that she had been sexually abused by her father and brother and told Baez that she feared that her father had tried to do something to Caylee and then tried to cover it up.
"The day that Casey actually told me what happened was long into the case. She was essentially the boy that cried wolf at this point in time in our case," Baez told "GMA." "What I tried to do was disprove what she was telling me and I just, quite frankly, I couldn't."
Baez said he was able to corroborate everything that Casey Anthony told him, so he believed her for several reasons.
"One, some of the evidence that corroborates it and there's a handful of pieces of evidence that came forward that she had no idea existed, so I knew that that was important to corroborate," he told "GMA." "And another thing was, I couldn't disprove it. This case was so heavily investigated, so thoroughly looked into when it came only to Casey so no stone was left unturned when I came to Casey."
On the anniversary of Anthony's acquittal and Baez described to "GMA" what he recalls from that life-changing day.
"I remember after the first not-guilty verdict I reached over and squeezed Casey's hand because it was a death penalty case and all I was concentrating on was saving her life," he said. "And after the second not-guilty verdict came, I squeezed her hand even tighter and then the third one...I think I may have cracked a bone at that point. I knew right then that my life was going to change and it certainly has."
Baez no longer represents Anthony who is currently on probation in Florida for a check fraud conviction. Does Baez still keep in touch with Anthony?
"I have contact with her like I have with any other previous client," he told "GMA." "But she is a previous client. I just certainly hope the she'll be able to go on with her life and make something of it.
Anthony has been in hiding since her acquittal and the court ordered her location to be kept secret because of death threats she has received. Her probation ends Aug. 21, 2012.
For more on this story, go to ABCNews.com.