Casey Anthony's defense attorney claimed in opening statements Tuesday that 2-year-old Caylee Anthony died after accidentally drowning in the family swimming pool.
Before that, Anthony had claimed her daughter was kidnapped.
Defense attorney Jose Baez said that Anthony never reported her daughter missing because it never happened.
"How in the world can a mother wait 30 days before ever reporting her child missing? It's insane. It's bizarre. Something's just not right about that. Well, the answer is relatively simply. She never was missing," said Baez, speaking from the Orange County Courthouse in Orlando, Fla.
"Caylee Anthony died on June 16, 2008 when she drowned in her family's swimming pool. You're going to hear that Caylee loved to swim and Caylee could get out of house very easily and did so on that day."
Anthony's defense attorney indicated that the mother's state of denial prevented her from informing authorities of her daughter's death.
"After Caylee died, Casey did what she has been doing all her life or for most of it, hiding her pain, going into that dark corner and pretending that she does not live in the situation that she is living in," said the lawyer. "She went to that deep, dark, ugly place called 'The Nile' to pretend as if nothing was wrong."
Added Baez, "You'll see as the evidence comes in that is the most likely conclusion of the evidence, that something is not right here. Something is not right with this girl.”
Casey Anthony is facing charges of first-degree murder. If found guilty, she could be sentenced to death. Her trial is being watched by 12 hand-picked jurors – five men and seven women from Clearwater, Fla.
An autopsy has never been able to conclude the cause of Caylee's death.
Earlier on Tuesday, prosecutor Linda Drane Burdick suggested that Caylee died from duct tape being placed over her mouth and nose. She also laid out a timeline of the events to argue that Anthony was a liar and murderer.
During prosecution opening statements, Anthony was seen narrowing her eyebrows and wiping tears with a tissue.