(NBC) — On Friday’s “Dateline,” the show examines the sudden disappearance of 12-year-old Jonelle Matthews, who mysteriously vanished from her Colorado home in 1984.

Here is a preview of Dennis Murphy’s report:

This is the place where he left her, Jonelle Matthews, abandoned — but not forgotten. It was just before Christmas in small town, Greeley, Colorado.

Deanna Ross was Jonelle’s childhood best friend. The two girls had just performed in their school’s Christmas concert and Deanna’s dad had driven them home.

DEANNA ROSS: She went inside and flicked the light on and off and then me and my dad left.

JENNIFER MATTHEWS: I came home around 10 o’clock and my dad had asked, “Do you know where Jonelle is?” Something was wrong.

12-year-old Jonelle Matthews was nowhere to be found. Reminders of the mystery were everywhere, but the clues were meager at best.

KEITH OLSON: Here’s the problem. We have no crime scene. And we have no body.

The case languished.

EILEEN HUFF: I thought, “Are you ever going to know what happened?”

But after years of dead ends, the Jonelle Matthews case had finally reached the twist.

Watch “Dateline: Footprints in the Snow” Friday at 9 p.m. on NBC4.

About ‘Dateline’

“Dateline NBC” is the longest-running series in NBC primetime history and is in its 33rd season. Dateline is anchored by Lester Holt and features correspondents Blayne Alexander, Andrea Canning, Josh Mankiewicz, Keith Morrison and Dennis Murphy.

The stories range from compelling mysteries to powerful documentaries and in-depth investigations. When major news breaks, they go to the scene, putting the pieces together to bring the viewer the full picture. And in every story they tell, they help the real people who lived the events share their journeys with the viewer.