(NBC News) — Tonight on an all-new “Dateline,” a young woman survives a brutal attack and detectives work tirelessly to find a suspect. But when they finally do, the victim is convinced they have the wrong man.

Here’s a preview of Keith Morrison’s report:

Detective Siobhan Seymour found Amber in the emergency room.

KEITH MORRISON: What was her condition when you got there?

DETECTIVE SIOBHAN SEYMOUR: She had suffered from a broken jaw, a brain bleed. One of her eyes was almost swollen shut. She had these ligature marks on her neck, where you could tell she had been strangled.

KEITH MORRISON: Strangled like somebody was trying’ to kill her or…

DETECTIVE SIOBHAN SEYMOUR: Yes. absolutely. She had a hard time speaking because her jaw hurt so badly.

Detective Seymour pushed ahead. Had to. But, medicated, exhausted, traumatized amber struggled to remember.

DETECTIVE SIOBHAN SEYMOUR: Tell me everything that you saw.

AMBER SMITH: I don’t know and I lost consciousness ’cause then the next thing I know, I woke up with my eyes taped and naked.

KEITH MORRISON: What kind of shape was she in emotionally?

DETECTIVE SIOBHAN SEYMOUR: She was afraid. ‘Cause she didn’t know who did this. And confused. She had thoughts of who might have done it. But she wasn’t sure.

She’d been with a guy, they’d been drinking. But they were in a different park, not the one where she was found. And the guy was a friend of hers.  She got out his name:  Aric Vanagunas.

DETECTIVE SIOBHAN SEYMOUR: You were drinking vodka?

AMBER SMITH: Mhm.

DETECTIVE SIOBHAN SEYMOUR:  Um, what’s the next thing that you remember?

AMBER SMITH:  The next thing I was waking up. There was some man on top of me.

“But who did this?”  Detective Seymour wondered. “Was it amber’s buddy Aric?  Or someone else altogether?”

The red duct tape. Severe beating. Strangulation.  Like some practiced predator was living out an awful fantasy.

DETECTIVE SIOBHAN SEYMOUR: I was feeling this intense need to figure out who had done this and fear for who this person that is out there and is capable of these things, like, we need to figure out who this guy is.

KEITH MORRISON: What was your level of worry about what could happen to this community if you did not find somebody quickly?

DETECTIVE SIOBHAN SEYMOUR: I was terrified that he was gonna strike again.

Watch “Dateline” tonight on NBC4 at 9 p.m.