The writer of the harmless letter to Mrs. Bernauer, a letter which chatted of household topics and touched lightly on the beauties of Venice, was Mrs. Thorne. It was Mrs. Thorne, therefore, who, reluctantly and in anger and distaste, had called Leopold Winkler to Hietzing, to his death.

And whose hand had fired the shot that caused his death? The question, at this stage in Muller's meditation, could hardly be called a question any more. It was all too sadly clear to him now.

Winkler met his death at the hand of the husband, who, discovering the planned rendezvous, had misunderstood its motive.

For truly this had been no lovers' meeting. It had been a meeting to which the woman was driven by fear and hate; the man by greed of gain. This was clearly proved by the 300 guldens found in the dead man's pocket, money enclosed in a delicate little envelope, sealed hastily, and crumpled as if it had been carried in a hot and trembling hand.

It was already known that Winkler never had any money except at certain irregular intervals, when he appeared to have come into possession of considerable sums. During these days he indulged in extravagant pleasures and spent his money with a recklessness which proved that he had not earned it by honest work.

Leopold Winkler was a blackmailer.

Colonel Leining, retired, the father of two such widely different children, was doubtless a man of stern principles, and an army officer as well, therefore a man with a doubly sensitive code of honour and a social position to maintain; and this man, morbidly sensitive probably, had a daughter who had inherited his sensitiveness and his high ideals of honour, a daughter married to a rich husband. But he had another child, a son without any sense of honour at all, who, although also an officer, failed to live in a manner worthy his position. This son was now in Marburg, where there were no expensive pleasures, no all-night cafes and gambling dens, for a man to lose his time in, his money, and his honour also.

For such must have been the case with Colonel Leining's son before his exile to Marburg. The old butler had hinted at the truth. The portrait drawn by Herbert Thorne, a picture of such technical excellence that it was doubtless a good likeness also, had given an ugly illustration to Franz's remarks. And there was something even more tangible to prove it: "Theo's" letter from Marburg pleading with Winkler for "discretion and silence," not knowing ("let us hope he did not know!" murmured Muller between set teeth) that the man who held him in his power because of some rascality, was being paid for his silence by the Lieutenant's sister.

It is easy to frighten a sensitive woman, so easy to make her believe the worst! And there is little such a tender-hearted woman will not do to save her aging father from pain and sorrow, perhaps even disgrace!

It must have been in this way that Mrs. Thorne came into the power of the scoundrel who paid with his life for his last attempt at blackmail.

When Muller reached this point in his chain of thought, he closed his eyes and covered his face with his hands, letting two pictures stand out clear before his mental vision.

He saw the little anxious group around the carriage in front of the Thorne mansion. He saw the pale, frail woman leaning back on the cushions, and the husband bending over her in tender care. And then he saw Johann Knoll in his cell, a man with little manhood left in him, a man sunk to the level of the brutes, a man who had already committed one crime against society, and who could never rise to the mental or spiritual standard of even the most mediocre of decent citizens.