(NBC News) — Friday on “Dateline,” a family begins a relentless pursuit of justice after the death of attorney Susan Winters is ruled a suicide.

Here is a preview of correspondent Josh Mankiewicz’s report:

It was a tragic loss — one that might have united a family in grief — instead, it tore them apart in anger.

AVIS WINTERS: It was just very cold and hostile.

CHRIS WINTERS: The lines were drawn, and he wasn’t backin’ off.

An open and shut case became a puzzle with a lot of missing pieces.

TONY SGRO: There’s a lot of trying to put a square peg in a round hole.

KATE BRIQUELET: There’s a lot of clues in this story, but no easy answers. It seems like it just doesn’t add up.

A family pushed back against the criminal justice system.

JOSH MANKIEWICZ: You knew that was gonna be the most uphill of uphill battles?

JULIE WINTERS: Yes.

CHRIS WINTERS: All we want to know is the truth.

And they refused to give up.

JOSH MANKIEWICZ: “You’re both grieving parents, and you need to let it go,” how many times did you hear that, and from how many people?

DANNY WINTERS: We heard it from everybody that we talked to.

AVIS WINTERS: But we’re stubborn people.

Watch an all-new “Dateline: A Cool Desert Morning,” Friday at 8 p.m. on KSN.

About ‘Dateline’

“Dateline NBC” is the longest-running series in NBC primetime history and is in its 31st season. Dateline is anchored by Lester Holt and features correspondents Andrea Canning, Josh Mankiewicz, Natalie Morales, Keith Morrison and Dennis Murphy.

Dateline is the #1 Friday newsmagazine and reaches more than 17 million people every week through its broadcast, and millions more through its social media platforms and podcasts.

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.