Two real-life incidents shaped A.J. Quinnell's development of the book. In the first, after the eldest son of a rich Singaporean was kidnapped by Triads for ransom money, the man refused to pay the ransom, leading to the death of his son; the refusal meant that the man's other children would not become targets. The second was the kidnapping of John Paul Getty III, the son of Paul Getty, in Rome.

Can we conclude that man on fire is it based on a true story?
yes