If he was to answer truthfully it would probably be something like this: "It did look like the TCU player was the last to touch the ball but since the TCU player losing the ball appeared to be because of a missed reach-in foul on ISU I just figured I would let the call stand."
It isn't the way it is supposed to be called, but that sure looked like what happened and, frankly, I can't get too upset about it.
And I would love for him to answer it that way. Because a missed foul call is no reason to not make the correct out of bounds call.
You don't go with a 100% wrong call just because you missed a foul.