Deborah Roberts

Premieres January 21st on FX, Hulu, and Hulu on Disney Plus for bundle subscribers.

Eastern on ESPN and the ESPN app.

Riley Gall's social media portrays him as the grieving boyfriend.

Police want to talk to him.

16 hours after Emma's body is discovered, Riley is brought in for questioning.

You have the right to remain silent.

Detectives with the Knox County Sheriff's Office want to know about his whereabouts over the past weekend.

Did that strike you as strange, that he couldn't remember if he spent the night here or what time he went there?

You know, we're talking about, you know, what'd you do yesterday and not what you did two years ago.

They were expecting, you know, someone who's 18, emotional, heartbroken.

And instead of referring to Emma by her name, he keeps calling her the girl.

If that's your girlfriend of two years who you're in love with, who you're posting these heartbreaking tributes to on social media, why aren't you using her name?

Riley tells them he'd been trying to speak with Emma all weekend, but she wouldn't engage, that she even blocked his number.

Riley offers police his alibi, saying after Emma hangs up on him, he goes to his grandparents' house, then drives back to his dorm where he breaks down in the parking lot.

I just sat there for about two to three hours and just wept, just looking at pictures of us and stuff like that.

He was really, really upset about this, but when you saw him, was he broken up?

He did not have the gun, didn't know where the gun was, and basically didn't have anything to do with it.

No, you had already talked to friends of his who had told you that he had this gun.

Yes, ma'am.

What if I told you someone told us that they saw you with a gun?