There's nothing to be done, we must go!" "Stay!" cried the young man suddenly.

"Do you see how the door shakes if you pull it ?" "Well ?" "That shows it's not locked, but fastened with the hook! Do you hear how the hook clanks ?" "Well ?" "Why, don't you see?
That proves that one of them is at home.

If they were all out, they would have locked the door from the outside with the key and not with the hook from inside.

There, do you hear how the hook is clanking?
To fasten the hook on the inside they must be at home, don't you see.

So there they are sitting inside and don't open the door!" "Well! And so they must be!" cried Koch, astonished.