(NBC News) — Tonight on all-new “Dateline,” just days before Christmas, high school senior Michelle Martinko is found stabbed to death in her car after visiting the mall. It would take almost 40 years for investigators to identify the killer — and when they did, Martinko’s family and friends were stunned.

Here’s a preview of Dennis Murphy report: 

It was the murder that cedar rapids, Iowa never forgot. Michelle Martinko the pretty high school senior with the Farrah Fawcett hairdo, yes it was that long ago.

She crossed this shopping mall parking lot, entered her father’s Buick, and was stabbed to death in a frenzied attack. Over the decades detectives talked to old boyfriends and others, but the case went nowhere.

Then they turned to the long-ago past and called upon sets of great-great-grandparents some of them born before the civil war to help with their murder investigation. What they found was astonishing. 

Watch “Dateline” tonight at 10 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.