(NBC) —Tonight on “Dateline,” a man’s wife dies in a house fire, then nearly 20 years later, his oldest son dies in a freak accident, prompting investigators to question his involvement.

Our story begins with a catastrophic fire in the old mining town of Murphy’s, California. It was New Year’s Day, 1991. A woman was trapped in a burning house. It seemed like every firefighter within radio range heard the call. They arrived at an awful scene.

Firefighter Rich Winn describes the scene, “Oh. It was just consuming the house. You know, we felt the smoke and the heat, you know, even from here. After 15, 20 minutes we got the fire knocked out. And then he chose two of us. My partner and I went in to find … to find the body. It was scary. And so as we went in the smoke is still rising. Water’s dripping everywhere. It’s a disaster scene. And then I heard him call out, ‘I found her.’  We just stop. And we — we just, you know, we’re so defeated. Dejected.”

Her name was Christina Karlsen. She was a 30-year-old wife and mother. Fortunately, maybe miraculously, her husband, Karl, and three young children had escaped the deadly blaze.  They were all being treated in an ambulance by paramedic Pam Giedt.

Giedt says talking to them wasn’t easy.

Geidt explains, “The children didn’t say much other than daddy had got them out of the house. They would answer things very briefly. They were not really connected, that I felt that they probably were suffering some sort of a psychological shock.”

That day was just the beginning of an epic drama involving the Karlsen family that we’ve been following for years.  And only now, nearly three decades since Christina’s death, can the secrets finally be revealed.

For the first time on television, the husband at the center of two murder investigations speaks out on “Dateline.”

“Dateline” airs tonight on NBC4 at 9 p.m., right after “Lincoln Rhyne: Hunt for the Bone Collector” for another “Crimetime Friday” you won’t want to miss.

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“Dateline NBC” is the longest-running series in NBC primetime history and is in its 28th season. “Dateline” is anchored by Lester Holt and features correspondents Andrea Canning, Josh Mankiewicz, Keith Morrison, and Dennis Murphy. Airing Fridays at 9 p.m.,  “Dateline” is the #1 Friday newsmagazine and reaches more than 16 million people every week through its broadcast, and millions more through its social media platforms and podcasts. Additionally,  “Dateline” closed out 2019 as the #1 Friday newsmagazine across the board.