(NBC News) — When young mother and paramedic Annamarie Cochrane Rintala was found dead at the bottom of her basement stairs, it took four trials and 13 years before justice was served.

In Friday’s “Dateline,” insiders close to the investigation speak out in new interviews about the final verdict.

Here is a preview of Dennis Murphy’s report:

The news of Ann Cochrane Rintala’s death reverberated among her friends and family for days. A young mother, her daughter still a toddler, was dead on the basement floor.

DENNIS MURPHY: How did you find out something awful had happened?

MARY PETRONE: I was at my desk at work. And — my wife at the time called me and said, “sit down.”

TJ DONAHUE: I heard there was an accident. That’s what I heard.

It looked as though Ann fell down those stairs. But, was it really an accident? Or something more sinister?

JAMIE MAGARIAN: I — I seriously —

DENNIS MURPHY: You couldn’t rule that out at that point.

JAMIE MAGARIAN: You can’t– you can’t rule anything out.

But Trooper Magarian was determined to find out.  Little did he know how long it would take.

Watch “Dateline: Down the Basement Stairs,” at 10 p.m. on NBC4.