Here was a son who had never been able to get on with his father, so much so that they could not live in the same house. To the father he had been a continual disappointment, and no doubt that irritation would show in the father’s manner, and could not but increase the bad blood between them. It was true they had agreed to differ, and Sir William had allowed Austin £1000 a year, but agreeing to differ did not necessarily prevent very unpleasant feelings on both sides, and as for the money, though it seemed handsome at first sight, it was very small compared to what Sir William might have paid without missing it. From what Tanner had seen of Austin and his villa, he thought the latter must be living at the rate of well on to a thousand a year. That was to say, nearly at the rate of his income. Under these circumstances he falls in love and decides to marry. The lady would have but a small dot, if any. The two of them must therefore live on what had before been enough for Austin only. What does Austin do? He sees his father the day after the engagement, probably to tell him the news, and possibly to ask for an increased allowance. As in the ordinary course of nature a large portion of Sir William’s money would soon become his in any case, this would not be an unreasonable demand. But what does Sir William answer? Tanner could only surmise, but from what the dead man had said to Mr Arbuthnot it was probable he had not only refused the increase, but had threatened altering his will adversely to Austin if the marriage took place. If, as appeared possible from the words overheard by Innes, Sir William had said anything derogatory to the lady, Austin’s feelings, already considerably aroused, would probably reach white heat. At all events, whether the interview between father and son had or had not taken this course, it was bed-rock fact that they had quarrelled about some woman. Tanner continued his surmises. Assuming he was correct so far, Austin would inevitably be faced with a very terrible temptation. If his father should die without altering his will, it would mean £150,000 to himself. £150,000! Quite a respectable sum of money! There would then be no question of love in a cottage with Miss Drew. He could give her all those things which men delight to give women. And the irritation of the constant unpleasantness with Sir William would be gone. The more Tanner considered the matter, the more powerful he felt this temptation would have been. Many a stronger man than Austin seemed to be had succumbed to less. Then coming down to details. The murderer had unquestionably known his way about Luce Manor. He had either gone to the library by the side door, and there committed the crime, carrying the body down to the boathouse, or, more probably, he had devised some scheme to make Sir William go there of his own accord. He had also taken the particular oars belonging to the boat used. All the knowledge necessary for this Austin of course possessed.