She stayed at the office for half an hour or so, enough time to brew herself a pot of red bush tea and to set her thoughts in order. The accidental discovery of the letter in the van had shocked and disturbed her. Mr. Polopetsi’s explanation of having found the letter in the garage was feasible enough, but there had been something about the manner in which he had made these protestations that did not ring true. He had hesitated, and when people hesitated it meant that either they were lying or they were thinking about your reaction to what they were about to say. But if she gave Mr. Polopetsi the benefit of the doubt and decided that he was hesitant merely because he feared her reaction to his explanation, she still had to answer why he would have harboured this fear. There was nothing wrong in what he had done—picking up a letter addressed to her and pocketing it with a view to passing it on later; so why should he have been furtive? It did not make sense, and that meant that he must have written the letter himself. It was an appalling conclusion—one that made her sit quite still, her head in her hands, even letting her cup of bush tea get cold, as she pondered the enormity of what she had inadvertently discovered: she had an enemy in the heart of the No. 1 Ladies’ Detective Agency, somebody whom she had trusted. And what had she done to deserve that? She could not answer that question. Pick as she might over all her dealings with the seemingly innocuous Mr. Polopetsi, she could not think of a single thing that she had done which would justify his enmity; not one thing. But then she thought: enmity does not require an unjust act to bring it into existence; sometimes simple envy is quite enough. Envy extended its tentacles into the chambers of the human heart, strangled what it found. Mr. Polopetsi was a poor man who had suffered great injustice—now he had so very little, while she had so much. That was what must have turned him. There might be an explanation for his behaviour, then, but that was very different from there being an excuse.

Mma Ramotswe shivered. The rain had lowered the temperature and the office was cool and dark. The sky had darkened again, grey shading into cloud-white; the sun had disappeared. She was alone in the office now, with only the apprentice outside, and, in the distance, the sound of cars moving through flooded sections of the road, some with their headlights still on from the storm. The absence of sun disconcerted her; it was as if the country was suddenly out of favour, deserted by its constant daytime companion.