Whilst his mother seems a bit… overbearing and even shifty, I have never really thought it was either the boyfriend or Matt, the prior boyfriend. I heard or read that they know the burner phone came to the area like a day or two prior and that it had spent the night at Vid’s address. I really don’t remember where that information came from, but I honestly don’t understand why they haven’t solved this if they know that much. If true, it seems like he must be in on it or at the very least know who is.