A Clue in Wax by Fred M. White

It was some hours later before Cheriton was able to visualise in a proper order the tense events that happened in the library at Holt. He just remembered, subconsciously, that he had been too late to see what had taken place between Seagrane and the midnight intruder, but in time to grapple with the man before he could get away. And in so doing he was taking a certain risk, because the burglar still had an automatic in his hand, and it was only the sudden appearance of Cheriton and his quick rush that had saved him from the same fate as the poor old man, lying silently there, evidently at his last gasp.

With a dexterous twist and turn, Cheriton was upon the man and had grasped him by the right wrist with a peculiar grip that he had learnt in the course of his police training. Then they had swayed to and fro towards the long, central window of the library that opened on to the terrace, after which the murderous assailant had managed to break away, leaving the torn rubber glove behind him and, what was more important, his revolver, before he dived headlong through the curtains and, by means of the open window, into the night.