How do we know that the boy is Liso? Papers: he has a passport that says that he is Liso Molapo. He has a birth certificate that says same. The aunt says that he is Liso Molapo. If he is not, then somebody is lying. The passport? The birth certificate? The aunt?

She put down her pen and looked at what she had written so far. It seemed to her that the important questions had been asked, and now it was simply a matter of finding answers. That, however, was the difficult part; questions were easy enough to pose, but the answers to these questions were not always ready at hand. There was, however, one very obvious answer, and it was the one that she thought she should consider before she looked at any other possibilities. This was that Liso Molapo was indeed Liso Molapo, and that Mma Sheba’s doubts were unfounded, and even ill-intentioned. Did Clovis Andersen say something about that? She rose to her feet and took the well-thumbed copy of The Principles of Private Detection from the shelf above the filing cabinet.

It did not take her long to find the relevant passage, and she read it out loud just as she would have done had Mma Makutsi been there. Remember, wrote Clovis Andersen, that of all the possibilities you may address, the truth may lie in the simplest explanation. So if you are looking for something that is stolen, always remember that it may not be stolen at all, but mislaid. Similarly, if you are investigating a homicide, it is always possible that the victim died a natural death. Do not exclude this possibility even where the death seems very suspicious. I knew a man who stabbed himself to death. Everybody thought that he had been murdered, and they found plenty of suspects – he was one heck of an unpopular guy – but then they discovered a note in which he said that he was going to do this in order to make things look bad for his principal enemy. He even used his enemy’s knife to do it!

Mma Ramotswe let out a little cry, half of surprise, half of disapproval. She had forgotten about that example but now it came back to her. It must be very unusual to stab oneself; people shot or poisoned themselves, but self-inflicted stabbing was an altogether different matter. She reminded herself that there was nothing like that in this case. Yet Clovis Andersen’s words brought home to her that it was entirely possible that Liso Molapo was quite genuine. Indeed, the more she thought about it, the more she felt that this was the likely outcome and that… She stopped herself. Was it possible that Mma Sheba stood to benefit in some way if the legacy of the farm to the boy were to fail? What if he were really Liso but was shown, falsely perhaps, to be an imposter? Who would get the farm then?