Nearly 20 years after the murder of his sister, JonBenet Ramsey’s brother will speak publicly for the first time about the mystery that has gripped America.

Read: Nearly 20 Years After JonBenet Ramsey's Murder, Where is Her Family Today?

Burke Ramsey, 29, will appear in a special three-part season premiere of Dr. Phil starting Monday, September 12, about the case that made headlines around the world.

In a new clip from the upcoming episodes, Dr. Phil McGraw presses Burke on why he has never spoken out until now, and why he chose his show to do so.

In the new clip, it appears Dr. Phil has taken him back to his childhood home in Boulder, Colorado.

During the series, he will reveal never-before-heard details about the case, according to the show.

His pageant star sister, then 6, vanished on Christmas Day 1996. Burke was 9 at the time.

Read: Stats Show Most Abducted Children Know Their Captors

JonBenet's body was found the next day in the basement of her family's home, just a day after she was reported missing.

She had been beaten and strangled on December 26, 1996, hours after she disappeared.

The case has never been solved and investigators continue to search for the killer.

Watch: Police in Desperate Search for 5-Year-Old Girl After Mother Is Found Dead in Apartment