They had been neatly stopped with putty and covered with knotting, and were so nearly the colour of the grained and varnished woodwork as to be hardly visible.
"Evidently," I answered, "there has been a bolt there, though it seems a queer place to fix one." "Not at all," replied Thorndyke.

"If you look up you will see that there was another at the top of the door, and, as the lock is in the middle, they must have been highly effective.

But there are one or two other points that strike one.

First, you will notice that the bolts have been fixed on quite recently, for the paint that they covered is of the same grimy tint as that on the rest of the door.

Next, they have been taken off, which, seeing that they could hardly have been worth the trouble of removal, seems to suggest that the person who fixed them considered that their presence might appear remarkable, while the screw-holes, which have been so skilfully and carefully stopped, would be less conspicuous.
"Then, they are on the outside of the door--an unusual situation for bedroom bolts--and were of considerable size.