Debra Roberts

On the camera footage, you can see Liam bringing his arm up, showing Anthony how he wrapped his arm around Sarah's neck.

He says it took him half an hour to kill her.

Anthony plays it cool as Liam goes on describing his heist, as he calls it.

Anthony chimes in with an occasional, right, or yeah, like a good friend does while listening to a story.

But Anthony doesn't need to coax Liam.

The story comes rushing out.

Listening to Liam, he sounds eager, like he's finally able to talk to someone about what he did and how he got away with it.

Detectives nearby cannot believe what they're hearing.

This Liam that they're hearing in the car was not the quiet and concerned friend they spoke to back at the station.

Then Liam starts to talk about how he got rid of Sarah's body.

And this is when police get another surprise.

We.

Liam says we threw Sarah off the bridge, meaning he didn't do it alone.

Investigators have been down the street listening to Liam tell Anthony how he killed Sarah Stern.

But he says he didn't do it alone.

Another one of Sarah's friends helped him.

Remember when Liam told officers he lost his phone the day Sarah disappeared?

Liam told Anthony he lost it at Sarah's house.

So he called on a friend to help him find his phone and hide Sarah's body.

Liam says Preston, as in Preston Taylor, his roommate and another friend of Sarah's.