It worked when the subject was O.J. Simpson. So why not when it's JonBenet Ramsey?

Almost 20 years after the six-year-old beauty queen was found dead in her family's Boulder, Colo. home, the baffling case is coming back to the TV airwaves big time starting next month.. Wednesday's separate announcements of major new productions from CBS and Lifetime follows last week's news that JonBenet's now 29-year-old brother, Burke, will be featured in a three-part exclusive interview on the Dr. Phil show airing in September.

The networks clearly are hoping to harness the same fascination with controversial true crime cases that made major hits of two O.J.-themed series during the same five month period this year. FX’s limited series, “The People vs. O.J. Simpson: American Crime Story,” became the cable network’s highest rated new series ever when it premiered in February and recently snagged 14 Emmy nominations. In June, ESPN premiered a  five-part documentary, “O. J.: Made in America” to similarly enthusiastic acclaim.

JonBenet’s beaten and strangled body was discovered in the basement of the Ramseys’ home on Dec. 26, 1996. Despite plenty of theories and fingerpointing, the murder remains unsolved to this day. JonBenet is buried in Marietta next to her mother, Patsy, who succumbed to cancer in 2006.

CBS said Wednesday it  would air a six-hour, three-part documentary series beginning on Sept. 18. “The Case of: JonBenet Ramsey” will feature a painstaking recreation of the crime scene and bring together original investigators and prosecutors along with new experts to examine the two decade old evidence using today's technology.

Lifetime, meanwhile, is going the TV movie route. The cable colossus that’s already turned the real life stories of everyone from Whitney Houston and Anna Nicole Smith to William and Kate into highly-rated flicks, has begun production on “Who Killed JonBenet?” The original movie to air sometime in the fall starts with the 911 call from the Ramsey home and “with the addition of recently surfaced information … takes a fresh look at the events and the competing theories about the murder,” Lifetime says.