Right.
But if this witness is correct, that she encountered some dark stranger on the street at 3:38 a.m., instead of being in JR's room as he said, why would he lie?
If the witness story that a stranger grabbed her is true, why would JR make this stuff up? He would truly have no idea at all what happened to her, and would have no reason to fabricate that she had used his phone to call Rohn.
I'm not sure about the Gatto witness, but I think it's possible that JR would have a reason to lie if he was doing something such as riding in the back of a truck during the time. His alibi would be that Lauren was still with him and hadn't left yet. Maybe he was out and about until 4:30 and wanted to cover for what he had been doing. Just speculation.