Did Casey Anthony Mouth Words During Rebuttal That Contradicts Own Defense?

July 5, 2011 — -- She declined to testify in her murder trial, but Casey Anthony was caught making inaudible remarks during the prosecution's rebuttal that may contradict her own defense.

WATCH: Casey Anthony Mouths Words at Trial: What Did She Say in Court?

Casey Anthony could be seen mouthing either "it's not his fault" or "because it's his fault" while prosecutor Linda Drane Burdick told the jury in the final moments of the case Monday that Casey Anthony was trying to pin responsibility for the death of her daughter Caylee on her father, George Anthony.

The defense has argued that 2-year-old Caylee wasn't murdered, but drowned accidentally in the family pool. They claimed that George Anthony found the girl's body and helped dispose of it. The defense also suggested that Casey's mother, Cindy Anthony, may have left in place the ladder into the pool.

Updated Evidence Photos of Casey Anthony Murder Trial

As Burdick told the jury, "Casey Anthony would have you believe that this is all her mother's fault anyway for leaving the ladder down, let's twist the knife in my mom a little bit more," Anthony can be seen on videotape saying something to herself.

Expert lip-reader Terry Ruane believes Anthony said, "I never said anything like that, it wouldn't have been my mom."

Ruane says that the full sentence uttered by Anthony appears to be, "I never said anything like that, wouldn't have been my mom. It isn't his fault."

Did Casey Anthony Contradict Her Own Defense?

If Ruane is correct, Casey Anthony is not placing blame on either of her parents.

HLN host Nancy Grace said today on "Good Morning America" that she thinks Casey Anthony said "it's not his fault."

"If she is in fact saying it's not his fault -- talking about George -- that breaks the defense case wide open because they, as opposed to proving an accidental drowning, have chosen to vilify George Anthony from the get go," said Grace.

ABC News' legal analyst Dan Abrams isn't so sure.

"It seems to me she could be saying 'It's his fault,'" said Abrams.

Both Abrams and Grace agree that if the jury noticed Anthony making remarks it could have an effect on their verdict. The jury, comprised of seven women and five men, are deliberating now for the first full day since receiving their charge.

"If the jury saw it, it might mean something," said Grace. "They were watching her."

Abrams adds, "It's important, the jurors are watching."

"Even if they're not directly looking at the defendant, they can see the defendant. They can try to look, they can look out of the side of their eyes," said Abrams.

The prosecution has argued throughout the trial that Anthony killed her daughter by drugging Caylee with chloroform and suffocating her with duct tape over her mouth and nose.

If the jury finds her guilty of first degree murder, Anthony would be eligible for the death penalty.