The Governors by E. Phillips Oppenheim

Virginia drew a little breath of relief. After all it had been very easy. She had simply walked into the flats, entered the lift, ascended to the fifth floor, opened the door of No. 57, and walked in. She had had a moment of fear lest there should be a servant in the rooms, but it was a fear which proved groundless. She had found herself in a tiny hall, with closed doors in front and on the right of her, and an open one on the left leading into a small, plainly furnished but comfortable sitting-room. This she entered, and closed the door behind her. At last she was in Norris Vine's sanctum.

She drew a little breath, half of relief, half of excitement, and then repenting at the closed door, quietly opened it, and left it about a foot ajar. She looked round the room with a swift comprehensive glance. There was only one place where it seemed possible that papers of importance might be hidden, a small desk with pigeon-holes, before the window. She sat down in front of it, and methodically, one by one, she examined every paper she found, bills, receipts, prospectuses, charitable appeals, circulars, memoranda of literary matter. She found many of these, but nothing in the least like the paper for which she was in search.