Tonight on Dateline. He was my person. Justin just wanted to be a dad so much. I love and I miss him and I really wish he was here.

She said, your brother's dead and I was like, what?

Justin was driven out to that desolate area by the lake, stabbed, and then eventually shot, yes. He deserved this.

I see the girls laying by the fire hydrant.

She was bleeding everywhere.

I got a call. Something's happened to your daughter. She had been murdered. It's beyond

thinkable. What would ignite such an evil murder of two people?

That pursuit was seen by nearly everybody in Southern California,

and now all of a sudden this feels like a much bigger plot.

Yes, it did. I've never had that happen.

Money, greed, jealousy.

If you left that night, you'd have been murdered, no question.

Yeah. It could have been murdered, no question. Yeah.

It could have been all of us.

One killing, then two.

Who was behind this dark double murder plot?

I'm Lester Holt, and this is Dateline.

Here's Josh Manchowitz with wrong turns.

In the wrong turns. It's impossible to know where life will take you.

Some roads lead to hope.

We were just really happy and again. Some roads lead to hope.

We were just really happy and excited.

...