It's unbelievable, isn't it, but that's how my sister came by her youngest cat. A family near them moved out, and left their three young cats behind. It was about a week before anyone cottoned on to what had happened, and a notice was left at the property, but no-one responded. The someone said they'd overheard they'd "done a moonlight flit" because they were in debt. So my sister took one cat, a friend of mine took the other, and the third went to a couple further up the street.
Hope these two babies get sorted out with homes, and more to the point that you can locate the second cat safely.