What does a bowl of pineapple have to do with the JonBenét Ramsey murder?

On the fateful afternoon of December 26, 1996, six-year-old child beauty queen JonBenét Ramsey was found dead in the basement of her family home with a nylon cord around her neck and her wrists tied above her head.

Her mouth was covered by duct tape and the results of the autopsy revealed that she had been killed by strangulation and a skull fracture.

The official cause of death was asphyxiation due to strangulation associated with craniocerebral trauma – and there was no evidence of conventional rape.

Her parents John and Patsy, and brother Burke, were cleared of her murder in 2008 following new DNA evidence from the victim's underwear that didn't match theirs.

The three members of the family were the only ones at the home in Boulder, Colorado, on the day of JonBenét's disappearance.

Two decades on, the unsolved murder case has been revisited. The appearance on The Dr Phil Show in a three-part-series by the victim's 29-year-old brother, Burke Ramsey, has created a media storm – in the show, he openly discusses his sister's murder for the very first time.

Burke, who was just nine years old when his sister died, sparked debate over whether he is guilty of the murder due to his alleged awkward behaviour - constant smiling – during the Dr Phil appearance.

Body language specialist Judi James explained his behaviour in an exclusive chat with IBTimes UK last week.

Following the three-part series on CBS, which ended on Monday (19 September), another television show digging for new evidence and theories aired on Channel Nine in the US for a two-part series – The Case Of: JonBenét Ramsey.

Former FBI special agent Jim Clemente claimed that he and his whole team have come to an agreement on who they believe murdered the beauty queen 20 years ago.

Results of the autopsy revealed that JonBenét had eaten pineapple only a few hours before her death – and photographs of the home taken on the day she was found show a bowl of pineapple on the kitchen table with a spoon in it. Though this may seem like an inconsequential detail, the pineapple became a main pointer as to who Clemente and his team think killed the little girl.

JonBenét murder theories:

Clemente's theory: The former FBI agent and his team are pointing the finger at the victim's brother, Burke. They predict that it was accidental rather than intentional, claiming that Burke had already struck his sister with a gold club after "losing his temper" – leaving her with a scar on her face a year before her death.

James Kolar, the former chief investigator for the District Attorney in Boulder, presented this theory which other experts agreed with. He cites that Patsy had left Burke with a bowl of pineapple and some tea. When JonBenét had some of the fruit for herself, nine-year-old Burke lashed out and struck her with a flashlight, resulting in her death.

He said: "My hypothesis was that I think the Ramseys came home at around 9.30, 10 o'clock," Kolar said.

"I think JonBenét was asleep. I think John did carry her upstairs, Patsy remained downstairs with Burke and served him the tea and the pineapple.

"I think that accounts for the physical evidence as well as the latent print. Then she got JonBenét up to make sure she used the toilet, so she didn't wet the bed that night.

"JonBenét was up, she may or may not have brushed her teeth, that stuff was out on the counter, then I think she was up and awake enough that she was maybe still hungry and she went downstairs," he added.

"In the meantime, Patsy continued packing for the Michigan trip. I think if Burke was upset about circumstances or Christmas presents, he probably would have been upset about her trying to snag a piece of pineapple – out of anger he may have struck her with that flashlight," he continued.

And while there was no intent to kill, the investigators all agree that there was clearly an intent to mislead the police investigation.

Former FBI profiler Clemente said: "The Ramsey family did not want law enforcement to resolve this case and that's why it remains unresolved."

The Ramsey's lack of cooperation with the police was "atypical" according to Clemente and the other investigators, as most families are desperate to resolve the case. FBI agent James Fitzgerald supported this claim, adding: "We didn't see that here, But maybe we did. Maybe we saw it with her brother – do everything we can to protect this child. We see it with the [ransom] letter. We see it in the press conference. Every step along the way we see it."

Investigators believe Burke was not part of a cover up – but say the mixed motives in the ransom letter indicate that both parents were. Read the ransom letter in full – one of the most confusing aspects of the murder inquiry – below. The ransom letter declaring JonBenét had been abducted made no sense as her body was found in the house hours after she went missing. It was abnormally long and asked for almost the same exact amount as the bonus that John had been given that year.

The Case Of documentary explained that multiple lines from the note were taken from movies like Dirty Harry and Speed. A forensic linguistics expert also noted that the letter used language such as "maternal" and included deliberate misspellings.

The first part of the chilling documentary revealed a six extra second of audio from a 911 call that appeared to suggest the family were involved. Modern technology was able to unveil the voices of three people having a conversation after Patsy thought the phone call to the police had ended.

The Case Of experts managed to slow it down enough to hear what sounded like JonBenét's father John Ramsey saying: "We're not speaking to you." Patsy then said: "What did you do?" and "Help me, Jesus," and a small child, probably nine year-old Burke saying, "What did you find?"

The 911 operator heard even more, including Patsy saying:"OK, we've called the police, now what?"

Burke's theory: The victim's shy and quiet brother, Burke, doesn't appear to have any theory of how his little sister was killed other than the fact it definitely wasn't him. Burke responded to the theory that his parents covered up JonBenét's murder in the third instalment of his interview with Dr Phil on Monday (19 September).

He said: "I don't know what to say to that, because I know that's not what happened. There's been people who have said that's not even physically possible for a nine-year-old to do that," he stated.

"Like you won't find any evidence, because I didn't do it." He also answered a categorical "no" after Dr Phil asked him if he had killed JonBenét.

Because male DNA was found under JonBenét's fignernails – suggesting she had "clawed her attacker" – police were given a "strong suggestion" that the Ramsey's were not involved in the murder and Burke and his parents were ruled out as suspects. He added: "Look at the evidence or the lack thereof."

On who he believes might have killed his sister, he remarked: "I kinda always just thought it was a paedophile, who saw her at one of the pageants, snuck in, who knows?"

The case is still unsolved.