The House of the Schemers by Fred M. White

Ailsa stood there with a certain curious exultation in the knowledge that she was no longer afraid. Here was a real and tangible danger, so different to those suggested by the utter loneliness of the dreary old home. This was no spirit from the other world, but a real, live man, who had no business here. He was a burglar, after some of the valuables with which the house was crammed, and it was Ailsa's obvious duty to hand him over to the police without delay.

But was he no more than the average burglar? It seemed absurd to think so; but Ailsa's instinct told her that there was something more than met the eye. As she stood there she could hear the passing cabs outside and the tramp of a policeman trudging along his beat. It would have been so easy for Ailsa to slip quietly down the stairs and call the officer in.