Sounds like the bees didn't move into her wall but a swarm alighted on her wall while waiting to find a permanent home. The few bees that you found after the swarm left were the after swarm, the bees that were out while the swarm left for their new permanent home. In my expereince they eventually find their way, probably back to their orginal hive. Haven't kept count of how many times over the years someone called me to come collect a swarm and by the time I showed up, all that was left was the afterswarm.