These payments were made almost exclusively by European governments, who funnel the money through a network of proxies, sometimes masking it as development aid, according to interviews conducted for this article with former hostages, negotiators, diplomats and government officials in 10 countries in Europe, Africa and the Middle East. The inner workings of the kidnapping business were also revealed in thousands of pages of internal Qaeda documents found by this reporter while on assignment for The Associated Press in northern Mali last year.

In its early years Al Qaeda received most of its money from deep-pocketed donors, but counterterrorism officials now believe the group finances the bulk of its recruitment, training and arms purchases from ransoms paid to free Europeans.

Put more bluntly, Europe has become an inadvertent underwriter of Al Qaeda.