(NBC News) — When history teacher and former Georgia beauty queen Tara Grinstead vanishes, detectives begin an investigation that will span over a decade. Just when it seemed the mystery would never be solved, a twist changes everything.

Tonight’s episode, “The Disappearance of Tara Grinstead,” features new details and interviews with  Tara’s friend Maria Harber, Tara’s ex-boyfriend Marcus Harper, Tara’s former student Dana Wilder and more.

Here’s a preview of Andrea Canning’s report:

There are certain stories that capture the imagination — turn into obsession.  A missing woman — a former beauty queen.  Her name was Tara Grinstead.

It was a search that spanned more than a decade.

CHRISTY WHEELER: It’s a mind-bender. You’re going in all directions.

From national news to crazy online theories, even a true-crime podcast.

PAYNE LINDSEY:  Somewhere in this network of people was the answer. The deeper you dig in this case, the more weird stuff you’re gonna find.

Everyone was asking: Where was tara? Tonight we have new details, with the latest developments in the case.

PROSECUTOR: Who was it that you were told killed Tara Grinstead?

And crucial new evidence.

BO DUKES: We drove back into the back. And he showed me where her body was.

ASHLEIGH MERCHANT: There’s a lot of small-town gossip everybody has their theory.

WENDY MCFARLAND: I was absolutely shocked.

That’s tonight on “Dateline NBC” at 10 p.m. on NBC4, followed by NBC4 at 11.