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Twenty years after the unsolved murder of JonBenet Ramsey, the brother of the 6-year-old beauty queen is breaking his silence in a series of interviews that will provide "great clarity" about the girl's mysterious death.

Ramsey's brother, Burke -- who was 9 years old at the time of the murder -- is speaking publicly for the first time in a series of interviews with "Dr. Phil." The interviews are set to air on Sept. 12, 13 and 19.

Dr. Phil told Fox News on Monday that he uncovered three tapes -- previously reported as lost -- that show Burke speaking with a psychologist and two interrogators in the days after his sister's murder inside the family's Colorado mansion on Dec. 25 or 26, 1996.

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JonBenet Ramsey (AP)

Dr. Phil referred to Burke, now 29, as the "missing link" in the case because he's never before spoken publicly about his sister's death.

"This thing has been examined from every angle you can possibly imagine and it has never gotten cold. All over the Internet, there's these three factions: the intruder did it, the Ramseys did it or Burke did it," he said.

"You're going to hear some things from the only other person known to be in the house the night of the murder and he speaks very openly," Dr. Phil said, though he declined to elaborate further.

"I ask him straight up, 'Did you murder your sister JonBenet Ramsey? I watch him watch those tapes and it was interesting to see his reaction to himself," he said. "Whatever your opinion is, it will be different after you watch these shows. I promise you, when this over, there will be great clarity about this very mysterious death."

Promotional clips of the interviews show Ramsey at times smiling when speaking about the morning his sister was discovered dead in the basement of the family home about eight hours after she was reported missing. She had been struck on the head and strangled.

When asked about the smiling, Dr. Phil noted, "There is unusual affect when he's talking about otherwise very deep and dark content but he is socially uncomfortable.

"He works remotely as a computer anaylyst. He doesnt go into the office. He's not around people a lot. He's very intelligent," he told Fox News.

In an excerpt from the interviews, Burke Ramsey admits, “I know people think I did it; that my parents did it." He then reveals for the first time what he believes happened to his sister.

"The first thing I remember is my mom bursting into my room really frantic saying, ‘Oh my gosh, oh my gosh,’ running around my room, now, I know, looking for JonBenet," he said.

JonBenet Ramsey was found by her father beaten and strangled in the basement after her mother called 911 hours earlier. A garrote made from a length of cord and the broken handle of a paintbrush had been used to strangle the girl. The autopsy also revealed that JonBenét had eaten pineapple only a few hours before the murder.

A two-and-a-half-page ransom letter was also found on the kitchen staircase demanding $118,000 for the girl's safe return. The figure was almost the exact value of a bonus her father, John, had received earlier that year.

Images of the blonde girl competing in child beauty pageants helped propel the case into one of the highest-profile mysteries in the country.

DNA was found beneath JonBenet's fingernails and inside her underwear, but family attorney Lin Wood said detectives were unable to match it to anyone in an FBI database.

Investigators said at one point that JonBenet's parents were under an "umbrella of suspicion" in the slaying, and some news accounts cast suspicion on JonBenet's older brother, Burke.

But the Ramseys insisted an intruder killed their daughter, and no one was ever charged.

Over the years, some experts suggested that investigators had botched the case so thoroughly that it might never be solved.