German banner Elsani & Neary Media and France’s Mediawan Rights are teaming up on “The Promise,” a true-crime TV series revolving around the gruesome murders of Nancy and Derek Haysom in 1985.

“The Promise” will tell the story of Jens Soering, who spent more than three decades in prison for the double murder of Nancy and Derek Haysom, the parents of his girlfriend at the time, Elizabeth Haysom. The latter was convicted of orchestrating the murder and sentenced to 90 years in prison. Soering was recently deported to Germany and Haysom to Canada. To this day, the chilling double murder case has not been entirely solved as new DNA evidence pointed to the presence of two unidentified men at the crime scene.

Showrunners for “The Promise” are Anita Elsani (“55 Steps”) and Ron Markus (“Bad Banks”), who is also executive producer. Marcus Vetter, who previously directed “Killing for Love,” a critically acclaimed true crime documentary about the case, has been tapped to work on the show.

The six-part series opens in 1984 at the University of Virginia, where Jens, a gifted student from Germany, falls in love with fellow student Elizabeth Haysom, an attractive young woman from a privileged background. Their passionate campus love story turns into a nightmare when Elizabeth’s wealthy parents are murdered in an act of inexplicable violence. Jens confesses to the murder only to later retract. The young German’s murder trial — one of the first to be broadcast live on television — makes international headlines.

Jens, who has been claiming his innocence all along, wrote six books while in prison and has received the support of many public figures, including former Germany president Christian Wulff, best-selling author John Grisham and actor Martin Sheen.

“The story of Jens and Elizabeth is not only a crime thriller, but also a gripping love story about fateful dependence,” said Elsani. “The case remains unsolved to this day and the search for the truth continues.”

“Jens and Liz’s journey from college to prison connects two dots that seem unreachably far away. Their story almost tortures me, that’s how painful it is,” said Markus.

Vetter, meanwhile, said “the story of Jens and Elizabeth has been with (him) for almost a decade.”

“I’m delighted to be able to contribute my expertise as part of the creative team. A fictional series opens up a new narrative scope,” added Vetter.

Mediawan Rights’ managing director Valérie Vleeschhouwer described the series project as a “captivating and ambitious true crime project that will engage a global audience.”

Bastie Griese, managing director of MMC Movies Köln (“The Fabulous Destiny of Amelie Poulain”), is a co-producer on the show.