“Very well, Rra,” said Mma Ramotswe. “You could help me, or rather you could help that poor American woman. She is a mother. You had a mother. I could say to you, Think about that mother’s feelings, but I know that with a person like you that makes no difference. You do not care about that woman. Not just because she is a white woman, from far away; you wouldn’t care if she was a woman from your own village, would you?”

He grinned at her. “I told you. We have finished our talk.”

“But people who don’t care about others can sometimes be made to care,” she said.

He snorted. “In a minute I am going to telephone the Administration and tell them that there is a trespasser in my room. I could say that I found you trying to steal something. I could do that, you know. In fact, I think that is just what I might do. We have had trouble with casual thieves recently and they would send the security people pretty quickly. You might have difficulty explaining it all, Mrs Logician.”

“I wouldn’t do that, Rra,” she said. “You see, I know all about Angel.”

The effect was immediate. His body stiffened and again she smelled the acrid odour, stronger now.

“Yes,” she said. “I know about Angel and the examination paper. I have a statement back in my office. I can pull the chair from under you now, right now. What would you do in Gaborone as an unemployed university lecturer, Rra? Go back to your village? Help with the cattle again?”

Her words, she noted, were like axe blows. Extortion, she thought. Blackmail. This is how the blackmailer feels when he has his victim at his feet. Complete power.

“You cannot do that … I will deny … There is nothing to show …”

“I have all the proof they will need,” she said. “Angel, and another girl who is prepared to lie and say that you gave her exam questions. She is cross with you and she will lie. What she says is not true, but there will be two girls with the same story. We detectives call that corroboration, Rra. Courts like corroboration. They call it similar fact evidence. Your colleagues in the Law Department will tell you all about such evidence. Go and speak to them. They will explain the law to you.”

He moved his tongue between his teeth, as if to moisten his lips. She saw that, and she saw the damp patch of sweat under his armpits; one of his laces was undone, she noted, and the tie had a stain, coffee or tea.