FWIW, I don't believe they were referring to AJ's cell phone, rather WH's. WH told LE that he was at the gas station with AJ, but LE told him they had no video of them there, and that 'the' cell phone was pinging around my hotel. 'On my bed, next to me'. Since WH likes to play the pronoun game ever so much, I am speculating, but it seems reasonable to me that they think she was there at the hotel because WH said he was with her at the time, but his cell phone was pinging at the hotel.
...sigh... granted, it makes sense that they are referring to AJ's cell phone too, I suppose. Stoopid pronoun game.