"A tragic case, here in the news, Fairfax. A man has been found dead at sea."
"Read it, if you please, James."
"'Ronald MacDonald, a boating enthusiast, has been found dead in his motor cruiser, 220 kilometres from land. Shortly after daybreak, about 4 a.m. yesterday, the boat was found by an air search instituted after Mr MacDonald had been reported missing the previous night. The boat, with its engine still running, was heading out to sea at 6 knots. A helicopter was despatched to the scene to enable a police officer to be lowered on board the moving vessel to take control of it. The boat was being steered by its auto-pilot. Mr Macdonald, a diabetic, was dead in the cabin of his elegantly-appointed 24 foot boat. Quite likely he had died in a diabetic coma.'
Very tragic, don't you think, Fairfax?"
"Very suspicious, is what I think."
"But why?" Though it's a shocking thing, it all seems so plain and obvious."
"Oh, it is obvious, and plain, as the nose on your face."
"You leave me flabbergasted. Although I know your deductive powers far exceed any other living soul, why, in the wide world, are you so sure in this case?"
"Elementary, James. Consider this argument: The boat is on auto-pilot heading directly out to sea. Mr Macdonald, a diabetic, starts to feel the need for his medication. Apparently there is none on board, which draws the conclusion that there was nothing to prevent the coma from which he is said to have died. But he would not have died instantly; it takes hours before becoming comatose. So, when he realised he had no medication, why did he not reverse the auto-pilot and head for home and safety? Something is not right, here."
"I take your point, Fairfax."
"Who notified the police that he was missing? His wife?"
"No. It says here in the paper:
'About 9 o'clock, the police received a 'missing persons' call from an unidentified woman, who said that both MacDonald and his boat were missing. The police went to his home and spoke to his wife. It was not she who had called the police. In fact, she was unconcerned, saying that her husband was always pottering about in his boat and had on several occasions remained at sea overnight. She had last seen him at breakfast early that morning. He had then gone to his boat-shed, where he spent a lot of time, both day and night. Shortly after breakfast, at about 8 a.m., she, accompanied by her elder sister, who lived with them, left for the city to go shopping. They returned about sunset and although neither saw Mr MacDonald this was nothing unusual.'
What say you to that, Fairfax?"
"Apparently the unknown woman who made the 'missing persons' call knows Mr MacDonald fairly well for she went to his boat-shed and found the boat missing. My assumption is that she had an appointment to meet him about 8 p.m. With no sign of his boat on the sea, she became sufficiently alarmed to call the police, but chose not to call at the house to inform Mrs Macdonald.
Another point: because Mr MacDonald has remained overnight at sea on other occasions, he would have needed to use his medication. We may assume that he would be sure to maintain a supply in the boat's first-aid box, and yet when he is found dead there is none on board.
Now let's consider Mr MacDonald's sea voyage from two alternative points of view. Here is my first thought:
Assume he winches his boat out of the boat-shed and down the boat ramp and puts to sea about 8 a.m. When would he plan to return? I suggest he has an appointment to meet the unknown woman and would return no later than 8 p.m. How far could he sail in those 12 hours? At most, only six hours out and six hours back. If, during this journey, his diabetes began to cause him concern, it is more likely to occur at a time when he is already on his way home and possibly almost there.
Now to my alternative view:
Assume, as above, that the boat left on its journey at 8 a.m. At a speed of 6 knots, non-stop, it will travel 220 kilometres by 4 a.m. the following day. That could be in any number of directions. For example, up and down the coastline, close to shore, would total 220 kilometres. What do we find, however? The boat, in fact, when found, was 220 kilometres from shore which means it must have sailed a direct course straight out to sea. Would Mr MacDonald set the auto-pilot on such a course and at no time take over control? Never! Such action is beyond belief. Someone else set the auto-pilot. Someone put him aboard unconscious. His drink was probably very heavily doped and he may have been asleep during the diabetic attack that killed him. The boat's fuel tank would be filled with enough to take him far out to sea, but nowhere near enough to return if he happened to wake up. Within a couple of hours of departure the boat would be over the horizon and possibly lost forever."
"The second alternative seems the more plausible, Fairfax. Undoubtedly, it's murder. Whom do you suspect? Perhaps the unknown woman's husband? Only a strong man could have lifted MacDonald into the boat."
"Perhaps not one strong man, James, but two weak women. I suspect the sisters as accomplices. MacDonald's wife reveals little love for him but what would be of mutual interest for both sisters to be rid of him? The house. MacDonald and the unknown woman may have had a relationship but it might not be provable in a divorce court. An unfavourable outcome might remove the women from their comfortable sea-side abode. Some other way of eliminating MacDonald was, therefore, necessary. The sisters knew of his diabetes and need for medication. The means and method were available to take advantage of his condition and so they became killers."