…Johnson’s greatest military exploit was the capture of the then-president, Samuel Doe, whom he subsequently had tortured to death in front of him, an event so historic that Johnson thought it worthy of capture on video: a video of which he is sufficiently proud that he offered to show it to visiting foreigners.

In the video Johnson sits at a table drinking Budweiser while in front of him, naked and trussed like a chicken, sits the former president. Johnson orders Doe’s ears to be cut off, and they are. It becomes clear that one motives for the torture, apart from to procure Doe’s death, is to make him divulge,  before he expires, the numbers of his bank accounts in London, where it is assumed that he has salted away his ill-gotten gains.

Doe was not an admirable man, and no mean killer himself. It is widely believed that he participated personally in the massacre at St Peter’s Church, Monrovia, where about 600 people who had taken refuge there were mowed down with machine-guns by his men, maddened by their impending defeat at the hands of the rebels. The outlines of the bodies in the dried blood were still visible when I visited the church. I found a New Testament there, in which a young girl, Martha D. Z. Sonyah, recorded her decision to receive Christ as her Saviour seven days before she was shot and then buried in a mass grave.

Dr Ameche, a Nigerian long resident in Liberia, and practically the only doctor left in Monrovia still in practice at the time, told me how Johnson had had him up against the wall ready to shoot him because he had told Johnson that it was his duty as a doctor to treat the wounded of all sides…

Another man, a BBC correspondent, told me that he had personally witnessed Johnson killing a young man…I saw Johnson’s capacity for instantaneous change from affability to murderous rage when, to persuade me that behind the murderer was the philanthropist, he took me to an orphanage that his organisation ran. He patted a little boy on the head there who had a protuberant stomach (malnutrition and worms), and said, in Liberian English, ‘What the matter, you pregnant-o?’

When a psychopathic killer-at-large laughs, you laugh with him. But then a man came out of the orphanage to tell Johnson that there was no ‘soup’ for the children: none of the savoury accompaniment to the starch that was the staple food. Johnson turned on him with fury for having ­humiliated him in front of a foreigner. I wouldn’t have recommended the man as a risk for a life insurance company.