NBC has a set a two-hour Dateline special on the JonBenét Ramsey murder case, the latest such project to air ahead of the 20th anniversary of the still-unsolved killing.

Dateline NBC: Who Killed JonBenét?” airs Friday, September 9 at 9 PM ET/PT, 8 PM CT. The special will include the first TV interviews with former Boulder PD Detective Jane Harmer, former Denver PD Detective Tom Haney, along with never-before-seen case documents, according to the network.

In the special, Harmer tells Dateline NBC correspondent Josh Mankiewicz that she agreed with the grand jury recommendation to indict JonBenét Ramsey’s parents, saying: “I think that the grand jurors heard the evidence and came up with that conclusion and I would agree with their conclusion.” Harmer adds she also agreed with the district attorney’s decision not to pursue charges against the Ramseys and she explains why. The special also features an interview with Bob Whitson, a retired detective sergeant at Boulder PD who was at the Ramsey house on the day the murder investigation began.

This year marks 20 years since the six-year-old beauty queen was found dead in the basement of her family’s home in Boulder on December 26, 1996. In 1999, a grand jury recommended indictments against Ramsey’s parents, but district attorney Alex Hunter did not sign the indictments and decided not to take the case to trial. In 2008, Hunter’s successor, district attorney Mary Lacy, wrote a letter exonerating the Ramseys, based on DNA evidence. The case remains open.

NBC’s Dateline special joins a slew of other projects on the subject, including CBS’ event docuseries The Case Of: JonBenet Ramsey, which will air in three parts beginning September 18; Lifetime original movie Who Killed JonBenet? set for premiere in the fall; and Investigation Discovery’s three-night television event series premiering September 12. A feature also in the works – Casting JonBenet, directed by Kitty Green and produced by James Schamus’ Symbolic Exchange.

You can watch a preview clip of the Dateline special below: