I'm Lester Holt tonight on Deadline. She's the woman at the center of so many suspicious deaths.

Now a whole new twist in the case of Lori Vallow, Mommy Doomsday.

I know Lori's your first name, right?

I think it's her stage. Those interview rooms are Lori Vallow's stage.

Tonight, newly released evidence in this notorious web of murder.

Two dead children, two dead spouses. Her husband was shot to death.

He goes nuts. Goes nuts like yelling at screaming.

Yeah, yelling at screaming.

She essentially convinces the detective that she's a victim.

That's an incredible thing to see.

Tell me about Tyley in that interview room.

I heard yelling from like right outside my door.

It's really tragic because we all know how the story ends.

There's brand new stuff here that we have not heard.

Video tapes.

My kids are in the right danger.

Interviews.

What happened when you came out of the gun?

I said, put that down.

Audio recordings.

They could be up to something.

There was all for Lori and Chad to be together.

...