“Three years ago the state gave us funding to open an Islamic community center in the Oud West section of the city. I took a part-time job there as counselor. I help new arrivals find their footing. I help our people learn to speak proper Dutch. And I keep an eye on our angry young men. That’s where I first heard the rumor about a plot to shoot down a Jewish airplane.” He glanced at Gabriel to see his reaction. “When I looked into the matter further, I found out it was more than just a rumor, and so I told Professor Rosner. You have me to thank for the fact that two hundred and fifty Jews weren’t blown to pieces over Schiphol Airport.”

A pair of middle-aged homosexual men came toward them along the embankment. Ibrahim slowed his pace and lowered his gaze reflexively toward the paving stones.

“I have another job as well,” he said when the men were gone. “I work for a friend in the Ten Kate Market selling pots and pans. He pays me a share of what I take in and lets me leave the stall to pray. There’s a small mosque around the corner on the Jan Hazenstraat. It’s called the al-Hijrah Mosque. It has a well-deserved reputation for the extremism of its imam. There are many young men at the al-Hijrah. Young men whose minds are filled with images of jihad and terror. Young men who speak of martyrdom and blood. Young men who look to Osama bin Laden as a true Muslim. These young men believe in takfir. You know this term? Takfir?”