I noticed it when he was pointing to these rooms from the passage.

This grip looks as if it might have been made by a smaller hand, with slim fingers.
Look how close together the marks are! Unfortunately, that's about all we're likely to deduce from them, and I doubt if a finger-print expert will be able to help us.

Observe, there are no finger-prints--merely faint marks of the middle of the fingers, and a kind of blur for the thumb.

But the thing is suspicious, undoubtedly suspicious." "Still, the door was locked from inside," said Dawfield.

"We mustn't lose sight of that fact." "And the key was found in the room.