How Did Caylee Anthony Die? Breaking Down The Theories In The Controversial Case

What exactly happened to Caylee Anthony?

It's a question that's haunted investigators and the public ever since 2-year-old Caylee Anthony was reported missing on July 15, 2008. Caylee's grandmother, Cindy Anthony, called 911 three times to say Caylee was gone – and that she hadn't seen her alive for 31 days.

"It smells like there's been a dead body in the damn car," she told the operator at one point.

Caylee's mother, Casey Anthony, then 22, claimed in one of the calls that her daughter had been kidnapped by a sitter, one she later identified to law enforcement as Zenaida "Zanny" Gonzalez. Authorities soon ascertained no such woman existed, according to CBS News.

Caylee wouldn't be found for months, until December 2008. Her decomposing remains were discovered in a wooded area near the Anthonys' home in Orlando, Florida.

The mystery of whether Caylee was dead or alive had ended — however, the mystery of who killed her and how still lingers.

Caylee's body was found hidden in multiple plastic bags, with duct tape over her face, according to a CNN report at the time.

"This duct tape was clearly placed prior to decomposition, keeping the mandible in place,"  Dr. Jan Garavaglia, chief medical examiner for Orange County, wrote in the autopsy.

RELATED: Forensic Linguist Expert Breaks Down Casey Anthony’s Statements To Police

The cause of death was listed as a "homicide by undetermined means, " though, as they were unable to ascertain exactly how she had died.

Casey Anthony, who had failed to report her daughter missing for over a month, was arrested and charged with first-degree murder as well as aggravated child abuse, aggravated manslaughter of a child, and providing false information to law enforcement before the body was even found.

At her trial, prosecutors argued Casey, sick of the burden of being a mother, had used chloroform on her daughter before suffocating her with duct tape, according to CNN. (Someone at the Anthony residence had googled "chloroform" before Caylee vanished.) The defense, meanwhile, argued the death had been an accident: that Caylee had drowned in her family's pool, and Casey's father, George, had found her body and then covered up her death, convincing Casey it was the right way to proceed, the outlet reported.

This uncertainty over how Caylee had actually died helped sway some jurors and led to Casey's acquittal of the murder charges.

"Generally, none of us liked Casey Anthony at all," one anonymous male juror told PEOPLE Magazine a month after the trial. "She seems like a horrible person. But the prosecutors did not give us enough evidence to convict. They gave us a lot of stuff that makes us think she probably did something wrong, but not beyond a reasonable doubt."

Another juror, Jennifer Ford, elaborated on this decision in an interview with ABC News, saying the pool theory seemed more believable than the prosecutors' argument.

“If you’re going to charge someone with murder, don’t you have to know how they killed someone or why they might have killed someone or have something, where, when, why, how?” Ford said. “Those are important questions, and they were not answered.”

Ultimately, in July 2011, Casey Anthony was found not guilty of first-degree murder, aggravated child abuse, and aggravated manslaughter of a child. She was, however, found guilty of four misdemeanor counts of providing false information to law enforcement. She was sentenced to four years in jail with credit for time served, and was released 10 days after her sentencing, according to CNN.

No one else has ever been charged in connection with Caylee Anthony's death. Her cause of death remains unknown.

Casey discusses the case in further detail in the three-episode documentary “Casey Anthony: Where The Truth Lies,” streaming Nov. 29 on Peacock.